Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”)
Consolidation, Policy	The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could differ from those estimates.
Leases	LeasesEffective January 1, 2019 the Company adopted ASU 2016-02, Leases (“ASU 2016-02”) using the modified retrospective transition method, with the cumulative-effect adjustment to the opening balance of retained earnings as of the effective date. Under the modified retrospective approach, financial results reported in periods prior to 2019 are unchanged. The Company also elected the package of practical expedients included in the new standard, which among other things, does not require a reassessment of lease classifications. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). This ASU and subsequently issued amendments requiring most leases with durations greater than 12 months to be recognized on the balance sheet. The standard is effective for interim and annual reporting periods beginning after December 15, 2018. The standard was adopted using the modified retrospective approach with an effective date as of the beginning of the Company’s fiscal year, January 1, 2019. See Note 10 for more information. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, (“ASU 2016-13”). ASU 2016-13 replaces the incurred loss impairment methodology with an “expected loss” model which requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The new guidance is effective for annual periods beginning after December 15, 2019 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2020, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also enhances the existing guidance for consistent application of Topic 740. The new guidance is effective for annual periods beginning after December 15, 2020 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2021, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting and measurement of convertible instruments and also adds disclosure requirements. Further, ASU 2020-06 simplifies the settlement assessment performed to determine whether a contract in the Company’s own equity qualifies for equity classification. The Company early adopted the standard effective January 1, 2021 using the modified retrospective approach, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. Given the Company’s IPO in April 2021, and based in part on the provisions of ASU 2020-06, warrants issued in conjunction with the CARES Act that may be settled in the Company’s own equity if publicly traded, were classified into equity during the second quarter of 2021. In November 2021, the FASB issued ASU 2021-10, Disclosures by Business Entities about Government Assistance (“ASU 2021-10”). ASU 2021-10 details financial reporting disclosure requirements that increase the transparency of transactions with a government accounted for by applying a grant or contribution accounting model by analogy. The new guidance is effective for annual periods beginning after December 15, 2021 and interim reporting periods within those reporting periods. The Company adopted the new standard as of December 15, 2021, which did not have an impact on the Company’s disclosures related to governmental grants or an impact to the results of operations and financial position as of the adoption date.
Cash and Cash Equivalents, Restricted Cash	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of acquisition to be cash and cash equivalents. Additionally, any items with maturities greater than three months that are readily convertible to known amounts of cash are considered cash and cash equivalents. Investments included in this category primarily consist of money market funds and time deposits. Restricted Cash Restricted cash may include certificates of deposit that secure letters of credit issued for particular airport authorities as required in certain lease agreements. The Company holds restricted cash to secure medical claims paid. Restricted cash may also include funds held as collateral for future travel paid with a credit card. These funds may be held by credit card processors directly under contracts that require a holdback of funds equal to a certain percentage of the related air traffic liability. If the Company fails to maintain certain liquidity and other financial covenants, the credit card processors’ rights to holdback would apply, which would result in a decrease of unrestricted cash. Restricted cash is carried at cost, which management believes approximates fair value.
Accounts Receivable, net	Accounts Receivable, netReceivables primarily consist of amounts due from credit card receivables, amounts due from aircraft lessors for maintenance performed, amounts due from select airport locations under revenue share agreements and incentives due from vendors. The Company records an allowance for credit losses for amounts not expected to be collected.
Supplies, net	Supplies, netSupplies consist of expendable aircraft spare parts, aircraft fuel and other supplies and are stated at the lower of cost or net realizable value. Supplies are accounted for on a first-in, first-out basis and are charged to expense as they are used. An allowance for obsolescence on expendable aircraft spare parts is provided over the remaining lease term or the estimated useful life of the related aircraft fleet to reduce the carrying cost of spare parts currently identified as excess to the lower of amortized cost or net realizable value.
Property and Equipment, net	Property and Equipment, net Property and equipment are stated at cost and depreciated on a straight-line basis over their estimated useful lives to their estimated residual values. The Company capitalizes additions, modifications enhancing the operating performance of its assets, and the interest related to payments used to acquire new aircraft and the construction of its facilities. The Company capitalizes interest attributable to pre-delivery payments (“PDPs”) as an additional cost of the related asset beginning when activities necessary to get the asset ready for its intended use commence. The Company capitalizes certain internal and external costs associated with the acquisition and development of internal-use software for new products and enhancements to existing products that have reached the application development stage and are deemed feasible. Capitalized costs include external direct costs of materials and services utilized in developing or obtaining internal-use software, and labor cost for employees who are directly associated with, and devote time to, internal-use software projects.
Asset Impairment	Asset Impairment The Company applies a fair value-based impairment test to the carrying amount of indefinite-lived intangible assets annually, or more frequently if certain events or circumstances indicate impairment. The Company assesses the value of indefinite-lived assets under a qualitative and quantitative approach, as required. Under a qualitative approach, the Company considers various market factors, including applicable key assumptions listed below. These factors are analyzed to determine if events and circumstances indicate that it is more likely than not that an indefinite-lived intangible asset's fair value is less than its carrying value. The quantitative approach is used to assess the asset’s fair value and the amount of the impairment. If the asset’s carrying amount exceeds its fair value calculated using the quantitative approach, an impairment charge is recorded for the difference in fair value and carrying amount. Indefinite-lived intangible assets are comprised of certain landing slot rights and the trademark of the Company. Factors that could result in future impairment of landing slot rights, holding other assumptions constant, include, but are not limited to: (i) significant reduction in demand for air travel, (ii) competitive activity in the slotted airport, (iii) anticipated changes to the regulatory environment such as diminished slot access and (iv) increased competition at a nearby airport. As part of this evaluation, the Company assesses whether changes in (i) macroeconomic conditions, (ii) industry and market conditions, (iii) cost factors, (iv) overall financial performance and (v) certain events specific to the Company, have occurred which would impact the use and/or fair value of these assets. As a result of the coronavirus (“COVID-19”) pandemic the Company performed a quantitative assessment on its indefinite lived intangibles during 2020 and determined no impairment charges were necessary. As a result of the continued recovery during 2021 and the substantial headroom between the book values and fair values of its indefinite lived intangibles assets determined as part of the 2020 quantitative assessment, the Company performed a qualitative assessment during 2021, which resulted in no impairments.The Company records impairment charges on long-lived assets used in operations and finite-lived intangible assets when events and circumstances indicate that the assets may be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets, and the net book value of the assets exceeds their estimated fair value. In making these determinations, the Company uses certain assumptions, including, but not limited to: (i) estimated fair value of the assets; and (ii) estimated undiscounted future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization including macroeconomic factors impacting future demand, length of service the asset will be used in the Company’s operations and estimated salvage values. There were no events or circumstances identified during 2021 that required the Company to perform a quantitative impairment assessment.
Aircraft Maintenance	Aircraft Maintenance The Company accounts for heavy maintenance and major overhauls under the deferral method, whereby the cost of heavy maintenance and major overhauls is deferred and recorded as flight equipment and depreciated over the lesser of the remaining lease term or the period until the next scheduled heavy maintenance event. The Company has separate maintenance cost-per-hour contracts for the repair of certain rotable parts to support airframe and engine maintenance and repair, as well as heavy maintenance and major overhauls. These agreements require monthly payments based upon utilization, such as flight hours, cycles and age of the aircraft. For the contracts in which risk has been determined to transfer to the service provider, expense is recognized based on the contractual terms of the cost-per-hour arrangement. For those contracts in which risk has not been determined to transfer to the service provider, the Company initially records monthly payments as a deposit and then accounts for the underlying maintenance event when it occurs, in accordance with the Company’s maintenance accounting policy. Certain of the Company’s aircraft lease agreements require the Company to pay maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. At lease inception and at each balance sheet date, the Company assesses whether the maintenance reserve payments required by its leases are substantively and contractually related to the maintenance of the leased asset. Maintenance reserve payments that are determined to be related to the maintenance of the leased asset are accounted for as maintenance deposits, to the extent they are expected to be recoverable, and are reflected as aircraft maintenance deposits on the Company’s consolidated balance sheets. When it is not probable that the Company will recover amounts currently on deposit with a lessor, such amounts are expensed as supplemental rent within aircraft rent in the Company’s consolidated statements of operations. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments and are not included within the right-of-use asset and respective lease liability. The Company makes certain assumptions at the inception of the lease and at each balance sheet date to determine the recoverability of maintenance deposits. These assumptions are based on various factors, such as the estimated time between the maintenance events, the cost of such maintenance events, the date the aircraft is due to be returned to the lessor and the number of flight hours and cycles the aircraft is estimated to be utilized before it is returned to the lessor. Changes in estimates are accounted for on a cumulative catch-up basis. On a regular basis, the Company assesses the credit worthiness of the Company’s lessors to ensure deposits are collectible. The Company continues to evaluate the creditworthiness of its lessors as a result of the COVID-19 pandemic downturns and specifically whether any credit losses existed for aircraft maintenance deposits and determined no allowance was necessary as of December 31, 2021 and 2020. Certain of the Company’s lease agreements provide that maintenance reserves held by the lessor at the expiration of the lease are nonrefundable to the Company and will be retained by the lessor. Consequently, any usage-based maintenance reserve payments after the last major maintenance event are not substantively related to the maintenance of the leased asset and, therefore, are accounted for as supplemental rent.
Leased Aircraft Return Costs	Leased Aircraft Return Costs The Company’s aircraft lease agreements generally contain provisions that require the Company to return aircraft airframes and engines to the lessor in a specified condition or pay an amount to the lessor based on the airframe and engine’s actual return condition. Lease return costs include all costs that would be incurred at the return of the aircraft, including costs incurred to repair the airframe and engines to the condition required by the lease. Lease return costs could include, but are not limited to, redelivery cost, redelivery crew cost, fuel, final inspections, reconfiguration of the cabin, repairs to the airframe, painting, overhaul of engines, replacement of components and checks. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost, there are various other factors which need to be considered such as current condition of the aircraft, the age of the aircraft at lease expiration, number of hours run on the engines, number of cycles run on the airframe, projected number of hours run on the engine at the time of return, the projected number of cycles run on the airframe at the time of return, the extent of repairs needed, if any, upon return, return locations, current configuration of the aircraft, current paint of the aircraft, estimated escalation of cost of repairs and materials at the time of return, current flight hour agreement rates and future flight hour agreement rates. In addition, typically near the lease return date, the lessors may allow maintenance reserves to be applied as return condition consideration or pass on certain return provisions if they do not align with their current plans to remarket the aircraft. As a result of the different factors listed above, management assesses the need to accrue lease return costs throughout the lease as facts and circumstances warrant an assessment. When costs become both probable and estimable, lease return costs are expensed as a component of aircraft rent in the consolidated statements of operations through the remaining lease term.
Derivative Instruments	Derivative Instruments Fuel Hedging Activities Variability in jet fuel prices impacts the Company’s results of operations. In order to reduce the risk of exposure to fuel price increases, the Company may enter into derivative contracts such as swaps, call options and collars. Derivative instruments are stated at fair value, net of any collateral postings. The Company formally designates and accounts for the derivative instruments that meet established accounting criteria under ASC 815, Derivatives and Hedging, as cash flow hedges. For derivative instruments that are designated and qualify as cash flow hedges, the gain or loss on the derivative instruments is recorded in accumulated other comprehensive income/loss (“AOCI/L”), a component of stockholders’ equity on the consolidated balance sheets. In general, the Company recognizes the associated gains or losses deferred in AOCI/L as a component of aircraft fuel expense within the consolidated statements of operations in the period that the aircraft fuel is consumed. For derivative instruments that are not designated as cash flow hedges, the gain or loss on the instrument is recognized in current period earnings. The Company presents its fuel derivative instruments net on the consolidated balance sheets. Refer to Note 7 for additional information regarding the Company’s hedge accounting and derivative instruments. Aircraft Purchase Hedging ActivitiesThe Company is party to certain interest rate swaption agreements that are accounted for as cash flow hedges, as defined under ASC 815, Derivatives and Hedging. Some of the Company’s aircraft purchase commitments can expose it to interest rate risk as, depending on the agreement, rental payments are adjusted and become fixed based on the seven or nine year swap rate at the time of delivery. The primary objective for interest rate derivatives is to hedge the portion of the estimated future monthly rental payments related to the associated agreement’s variable interest rate, historically London Interbank Offered Rate (“LIBOR”). These swaption agreements provide for a single payment at maturity based upon the change in the applicable swap rate between the execution date and the termination date. For derivative instruments that are designated and qualify as cash flow hedges, the gain or loss on the derivative instruments is recorded in AOCI/L. In general, the Company recognizes the associated gains or losses deferred in AOCI/L as a component of aircraft rent expense in the Company’s consolidated statements of operations over the life of the lease on a straight-line basis. The Company presents its interest rate swaption derivative instruments net on the consolidated balance sheets.
Aircraft Fuel	Aircraft FuelAircraft fuel expense includes jet fuel and associated into-plane costs, federal and state taxes and the amortized gains, losses and premiums associated with effective fuel hedge contracts within AOCI/L and gains and losses from ineffective or dedesignated fuel hedge contracts.
Sales and Marketing	Sales and MarketingSales and marketing expense includes credit card processing fees, system booking fees, sponsorship and distribution costs such as the costs of the Company’s call center and advertising costs. Advertising and the related production costs are expensed as incurred
Income Taxes	Income TaxesThe Company accounts for income taxes using the asset and liability method. Deferred income taxes are recognized for the tax consequences of temporary differences between the tax and financial statement reporting bases of assets and liabilities. The Company periodically assesses whether it is more likely than not that sufficient taxable income will be generated to realize deferred income tax assets, and a valuation allowance is established if it is not likely that deferred income tax assets will be realized. The Company considers sources of taxable income from prior period carryback periods, future reversals of existing taxable temporary differences, tax planning strategies and future projected taxable income when assessing the future realization of deferred tax assets. In assessing the sources of income and the need for a valuation allowance, the Company considers all available positive and negative evidence, which includes a recent history of cumulative losses.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes cost of employee services received in exchange for awards of equity instruments based on the fair value of each instrument at the date of grant. Compensation expense is recognized over the period during which an employee is required to provide service in exchange for an award, with forfeitures accounted for as they occur. The fair value of stock option awards is estimated on the date of grant using the Black-Scholes valuation model. Restricted stock awards and units are valued at the fair value of the shares on the date of grant. The exercise price of all stock awards is determined by the Company’s board of directors based, in part, on the ending stock price on the grant date. Prior to the Company’s IPO, there were significant judgments and estimates inherent in these valuations which included assumptions regarding the Company’s future operating performance, the time to complete potential liquidity events and the determinations of the appropriate valuation methods to be applied.
Recently Adopted Accounting Pronouncements	LeasesEffective January 1, 2019 the Company adopted ASU 2016-02, Leases (“ASU 2016-02”) using the modified retrospective transition method, with the cumulative-effect adjustment to the opening balance of retained earnings as of the effective date. Under the modified retrospective approach, financial results reported in periods prior to 2019 are unchanged. The Company also elected the package of practical expedients included in the new standard, which among other things, does not require a reassessment of lease classifications. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). This ASU and subsequently issued amendments requiring most leases with durations greater than 12 months to be recognized on the balance sheet. The standard is effective for interim and annual reporting periods beginning after December 15, 2018. The standard was adopted using the modified retrospective approach with an effective date as of the beginning of the Company’s fiscal year, January 1, 2019. See Note 10 for more information. In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, (“ASU 2016-13”). ASU 2016-13 replaces the incurred loss impairment methodology with an “expected loss” model which requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The new guidance is effective for annual periods beginning after December 15, 2019 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2020, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also enhances the existing guidance for consistent application of Topic 740. The new guidance is effective for annual periods beginning after December 15, 2020 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2021, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting and measurement of convertible instruments and also adds disclosure requirements. Further, ASU 2020-06 simplifies the settlement assessment performed to determine whether a contract in the Company’s own equity qualifies for equity classification. The Company early adopted the standard effective January 1, 2021 using the modified retrospective approach, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. Given the Company’s IPO in April 2021, and based in part on the provisions of ASU 2020-06, warrants issued in conjunction with the CARES Act that may be settled in the Company’s own equity if publicly traded, were classified into equity during the second quarter of 2021. In November 2021, the FASB issued ASU 2021-10, Disclosures by Business Entities about Government Assistance (“ASU 2021-10”). ASU 2021-10 details financial reporting disclosure requirements that increase the transparency of transactions with a government accounted for by applying a grant or contribution accounting model by analogy. The new guidance is effective for annual periods beginning after December 15, 2021 and interim reporting periods within those reporting periods. The Company adopted the new standard as of December 15, 2021, which did not have an impact on the Company’s disclosures related to governmental grants or an impact to the results of operations and financial position as of the adoption date.
Revenue from contract with customer	Passenger Revenues Fare revenues. Tickets sold in advance of the flight date are initially recorded as an air traffic liability on the Company’s consolidated balance sheets. Fare revenues are recognized in passenger revenues within the consolidated statements of operations at the time of departure when transportation is provided. As of December 31, 2020, the Company’s current air traffic liability balance was $135 million. During the year ended December 31, 2021, 89% of the air traffic liability as of December 31, 2020 has been recognized as passenger revenue within the consolidated statements of operations. As of December 31, 2021, the Company’s current air traffic liability is $273 million, of which $59 million is related to customer rights to book future travel, which either expire within 3 or 12 months after issuance if not redeemed by the customer. The amounts expected not to be redeemed are recognized over the historical pattern of rights exercised by customers to fare revenues in passenger revenues within the consolidated statements of operations. During the years ended December 31, 2021, 2020 and 2019, the Company recognized $58 million, $126 million and $26 million of revenue, respectively, in passenger revenues within the consolidated statements of operations, primarily related to expected and actual expiration of customer rights to book future travel. Estimated and actual expiration of customer rights to book future travel during the year ended December 31, 2020 was mainly due to the large amount of modifications of travel initiated by customers during late March through June 30, 2020 as a result of the COVID-19 pandemic. Non-fare passenger revenues. Certain ancillary items such as service fees, baggage and seat selection deemed part of providing passenger transportation are recognized to non-fare passenger revenues in passenger revenues within the consolidated statements of operations. Service fees include, among other things, convenience fees, charges for nonrefundable ticket expiration, cancellation charges and service charges assessed for itinerary changes made prior to the date of departure. Such change fees are recognized at the time of departure of the newly scheduled travel. Beginning in March 2020, resulting from the reduction in demand from the COVID-19 pandemic, the Company waived cancellation and change fees for customers for most of 2020 and the first quarter of 2021. Passenger Taxes and Fees. The Company is required to collect certain taxes and fees from customers on behalf of government agencies and airports and remit these back to the applicable governmental entity or airport on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, airport passenger facility charges, and foreign arrival and departure taxes. These taxes and fees are collected from customers at the time they purchase their tickets but are not included in passenger revenues at that time. The Company records a liability upon collection from the customer and reduces the liability when payments are remitted to the applicable governmental agency or airport. Other Revenues Other revenues primarily consists of services not directly related to providing transportation, such as the advertising, marketing and brand elements of the Frontier Miles affinity credit card program and commissions revenue from the third-party sale of items such as rental cars and hotels. Frequent Flyer Program The Company’s Frontier Miles frequent flyer program provides frequent flyer travel awards to program members based on accumulated mileage credits. Mileage credits are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for mileage credits earned by passengers under its Frontier Miles program based on the equivalent ticket value (“ETV”) a passenger receives by redeeming mileage credits for a ticket rather than paying cash. Mileage credits are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have three separate performance obligations: (i) mileage credits to be awarded, (ii) licensing of brand and access to member lists and (iii) advertising and marketing efforts. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For mileage credits, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of mileage credits needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace and industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation, the Company considers market-specific factors and entity-specific factors, including the Company’s internal costs of providing services, volume of marketing efforts and overall advertising plan. Consideration allocated based on the relative standalone selling price to both the brand licensing and access to member lists and advertising and marketing elements is recognized as other revenue in the Company’s consolidated statements of operations over time as mileage credits are delivered. The consideration allocated to the transportation portion of these mileage credit sales is deferred and recognized as a component of passenger revenue in the Company’s consolidated statements of operations at the time of travel for mileage credits redeemed. Mileage credits that the Company estimates are not likely to be redeemed are subject to breakage and are recognized as a portion of passenger revenues in the Company’s consolidated statements of operations in proportion to the pattern of rights exercised by customers. Management uses statistical models to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which mileage credits are expected to be redeemed, the actual redemption activity for mileage credits or the estimated fair value of mileage credits expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years. Redemptions are allocated between sold and flown mileage credits based on historical patterns. As a result of the reduction in demand due to the COVID-19 pandemic, beginning in March 2020, the Company extended the expiration dates of mileage credits issued under its frequent flyer program. During September 2020, the Company amended its credit card affinity agreement with its credit card partner Barclays. The amended and restated agreement, similar to the previous arrangement, provides for joint marketing, grants certain benefits to co-branded credit card holders, and allows Barclays to market using the Company’s customer database. Cardholders earn mileage credits under the Frontier Miles program and the Company sells mileage credits at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers. The amended and restated agreement extended the term from 2023 to 2029 and provided for an up-front non-refundable payment of $25 million to the Company, of which the unamortized portion is recorded within other current liabilities, other long-term liabilities, and long-term frequent flyer liability on the consolidated balance sheets. The non-refundable payment will be recognized as other revenue in the Company’s consolidated statements of operations over the contact period as the Company performs its performance obligations under the amended agreement.
Gains on Sale-Leaseback Transactions	Gains on Sale-Leaseback TransactionsThe Company enters into sale-leaseback transactions for its aircraft and aircraft engine assets, whereby the Company sells one or more aircraft or aircraft engine assets to a third-party and simultaneously enters into an operating lease for a right to use such assets for a fixed period of time. Gains on sale-leaseback transactions are recognized in the period in which title to the asset transfers to the buyer-lessor and the lease commences, as a component of other operating expenses within the consolidated statements of operations. Gains on sale-leaseback transactions are calculated as the excess of the sale price of the asset over its carrying value. The carrying value of the assets sold will generally include the price paid for the asset, net of the amount of cash or the fair value of non-cash credits and incentives received from equipment and component manufacturers, the costs associated with delivery of the asset including any taxes or tariffs, financing costs capitalized in connection with the construction of the asset, capitalized maintenance and other improvements, and accumulated depreciation. Gains on sale-leaseback transactions may also be adjusted if it is determined that the terms of the sale transaction or the lease agreement are at a price other than fair value.
Fair Value Measurement	Under ASC 820, Fair Value Measurements and Disclosures, disclosures relating to how fair value is determined for assets and liabilities are required, and a hierarchy for which these assets and liabilities must be grouped is established, based on significant levels of inputs, as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes several valuation techniques in order to assess the fair value of its financial assets and liabilities. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents are comprised of liquid money market funds, time deposits and cash and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value. Warrants The estimated fair value of the warrants issued in conjunction with the loans from the CARES Act, described in Note 2, was previously determined to be Level 3 measurement as of December 31, 2020. As a result of the Company’s IPO, the Company has the intent and ability to settle the warrants issued to the Treasury in shares and thus, as of April 6, 2021, the Company reclassified the warrant liability to additional paid-in capital on the consolidated balance sheet. Subsequent warrants issued after the IPO date were recorded at fair value as a reduction to the related debt they were issued with and recorded to additional paid-in capital on the consolidated balance sheet. As the warrants issued under the CARES Act will no longer be subject to recurring fair value measurements, they have been excluded from the table below as of December 31, 2021. Debt The estimated fair value of the Company’s debt agreements has been determined to be Level 3 measurement, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes a discounted cash flow method to estimate the fair value of the Level 3 long-term debt.
Operating Leases	The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related operating lease right-of-use asset and corresponding operating lease liability are recorded at the present value of lease payments over the term on the Company’s consolidated balance sheets. Some leases include rental escalation clauses, renewal options, termination options, and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components. When available, the rate implicit in the lease is used to discount lease payments to present value; however, most leases do not provide a readily determinable implicit rate. Therefore, the Company estimates its incremental borrowing rate (“IBR”) to discount the lease payments based on information available at lease commencement. The IBR utilized by the Company is first determined using an unsecured recourse borrowing rate over a tenor that matches the period of lease payments for each individual lease and then is adjusted to arrive at a rate that is representative of a collateralized rate (secured rate). Given the Company does not have an established unsecured public credit rating, the Company utilizes current period and projected financial information to simulate an unsecured credit rating. The Company then determines its secured rate (IBR) using a combination of several valuation methods that take into account the lower amount of risk of collateralized borrowings along with observable implied credit ratings from its current outstanding secured debt obligations.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Basis of PresentationThe consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”)

Consolidation, Policy

The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could differ from those estimates.

Leases

LeasesEffective January 1, 2019 the Company adopted ASU 2016-02, Leases (“ASU 2016-02”) using the modified retrospective transition method, with the cumulative-effect adjustment to the opening balance of retained earnings as of the effective date. Under the modified retrospective approach, financial results reported in periods prior to 2019 are unchanged. The Company also elected the package of practical expedients included in the new standard, which among other things, does not require a reassessment of lease classifications.

Recently Adopted Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). This ASU and subsequently issued amendments requiring most leases with durations greater than 12 months to be recognized on the balance sheet. The standard is effective for interim and annual reporting periods beginning after December 15, 2018. The

standard was adopted using the modified retrospective approach with an effective date as of the beginning of the Company’s fiscal year, January 1, 2019. See Note 10 for more information.

In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments, (“ASU 2016-13”). ASU 2016-13 replaces the incurred loss impairment methodology with an “expected loss” model which requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The new guidance is effective for annual periods beginning after December 15, 2019 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2020, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date.

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and also enhances the existing guidance for consistent application of Topic 740. The new guidance is effective for annual periods beginning after December 15, 2020 and interim reporting periods within those reporting periods. The Company adopted the new standard as of January 1, 2021, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date.

In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU 2020-06”). ASU 2020-06 simplifies the accounting and measurement of convertible instruments and also adds disclosure requirements. Further, ASU 2020-06 simplifies the settlement assessment performed to determine whether a contract in the Company’s own equity qualifies for equity classification. The Company early adopted the standard effective January 1, 2021 using the modified retrospective approach, which did not have a material impact on the Company’s results of operations or financial position as of the adoption date. Given the Company’s IPO in April 2021, and based in part on the provisions of ASU 2020-06, warrants issued in conjunction with the CARES Act that may be settled in the Company’s own equity if publicly traded, were classified into equity during the second quarter of 2021.

In November 2021, the FASB issued ASU 2021-10, Disclosures by Business Entities about Government Assistance (“ASU 2021-10”). ASU 2021-10 details financial reporting disclosure requirements that increase the transparency of transactions with a government accounted for by applying a grant or contribution accounting model by analogy. The new guidance is effective for annual periods beginning after December 15, 2021 and interim reporting periods within those reporting periods. The Company adopted the new standard as of December 15, 2021, which did not have an impact on the Company’s disclosures related to governmental grants or an impact to the results of operations and financial position as of the adoption date.

Cash and Cash Equivalents, Restricted Cash

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the date of acquisition to be cash and cash equivalents. Additionally, any items with maturities greater than three months that are readily convertible to known amounts of cash are considered cash and cash equivalents. Investments included in this category primarily consist of money market funds and time deposits.

Restricted Cash

Restricted cash may include certificates of deposit that secure letters of credit issued for particular airport authorities as required in certain lease agreements. The Company holds restricted cash to secure medical claims paid. Restricted cash may also include funds held as collateral for future travel paid with a credit card. These funds may be held by credit card processors directly under contracts that require a holdback of funds equal to a certain percentage of the related air traffic liability. If the Company fails to maintain certain liquidity and other financial covenants, the credit card processors’ rights to holdback would apply, which would result in a decrease of unrestricted cash. Restricted cash is carried at cost, which management believes approximates fair value.

Accounts Receivable, net

Accounts Receivable, netReceivables primarily consist of amounts due from credit card receivables, amounts due from aircraft lessors for maintenance performed, amounts due from select airport locations under revenue share agreements and incentives due from vendors. The Company records an allowance for credit losses for amounts not expected to be collected.

Supplies, net

Supplies, netSupplies consist of expendable aircraft spare parts, aircraft fuel and other supplies and are stated at the lower of cost or net realizable value. Supplies are accounted for on a first-in, first-out basis and are charged to expense as they are used. An allowance for obsolescence on expendable aircraft spare parts is provided over the remaining lease term or the estimated useful life of the related aircraft fleet to reduce the carrying cost of spare parts currently identified as excess to the lower of amortized cost or net realizable value.

Property and Equipment, net

Property and equipment are stated at cost and depreciated on a straight-line basis over their estimated useful lives to their estimated residual values. The Company capitalizes additions, modifications enhancing the operating performance of its assets, and the interest related to payments used to acquire new aircraft and the construction of its facilities. The Company capitalizes interest attributable to pre-delivery payments (“PDPs”) as an additional cost of the related asset beginning when activities necessary to get the asset ready for its intended use commence.

The Company capitalizes certain internal and external costs associated with the acquisition and development of internal-use software for new products and enhancements to existing products that have reached the application development stage and are deemed feasible. Capitalized costs include external direct costs of materials and services utilized in developing or obtaining internal-use software, and labor cost for employees who are directly associated with, and devote time to, internal-use software projects.

Asset Impairment

The Company applies a fair value-based impairment test to the carrying amount of indefinite-lived intangible assets annually, or more frequently if certain events or circumstances indicate impairment. The Company assesses the value of indefinite-lived assets under a qualitative and quantitative approach, as required. Under a qualitative approach, the Company considers various market factors, including applicable key assumptions listed below. These factors are analyzed to determine if events and circumstances indicate that it is more likely than not that an indefinite-lived intangible asset's fair value is less than its carrying value. The quantitative approach is used to assess the asset’s fair value and the amount of the impairment. If the asset’s carrying amount exceeds its fair value calculated using the quantitative approach, an impairment charge is recorded for the difference in fair value and carrying amount. Indefinite-lived intangible assets are comprised of certain landing slot rights and the trademark of the Company.

Factors that could result in future impairment of landing slot rights, holding other assumptions constant, include, but are not limited to: (i) significant reduction in demand for air travel, (ii) competitive activity in the slotted airport, (iii) anticipated changes to the regulatory environment such as diminished slot access and (iv) increased competition at a nearby airport. As part of this evaluation, the Company assesses whether changes in (i) macroeconomic conditions, (ii) industry and market conditions, (iii) cost factors, (iv) overall financial performance and (v) certain events specific to the Company, have occurred which would impact the use and/or fair value of these assets.

As a result of the coronavirus (“COVID-19”) pandemic the Company performed a quantitative assessment on its indefinite lived intangibles during 2020 and determined no impairment charges were necessary. As a result of the continued recovery during 2021 and the substantial headroom between the book values and fair values of its indefinite lived intangibles assets determined as part of the 2020 quantitative assessment, the Company performed a qualitative assessment during 2021, which resulted in no impairments.The Company records impairment charges on long-lived assets used in operations and finite-lived intangible assets when events and circumstances indicate that the assets may be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets, and the net book value of the assets exceeds their estimated fair value. In making these determinations, the Company uses certain assumptions, including, but not limited to: (i) estimated fair value of the assets; and (ii) estimated undiscounted future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization including macroeconomic factors impacting future demand, length of service the asset will be used in the Company’s operations and estimated salvage values. There were no events or circumstances identified during 2021 that required the Company to perform a quantitative impairment assessment.

Aircraft Maintenance

The Company accounts for heavy maintenance and major overhauls under the deferral method, whereby the cost of heavy maintenance and major overhauls is deferred and recorded as flight equipment and depreciated over the lesser of the remaining lease term or the period until the next scheduled heavy maintenance event. The Company has separate maintenance cost-per-hour contracts for the repair of certain rotable parts to support airframe and engine maintenance and repair, as well as heavy maintenance and major overhauls. These agreements require monthly payments based upon utilization, such as flight hours, cycles and age of the aircraft. For the contracts in which risk has been determined to transfer to the service provider, expense is recognized based on the contractual terms of the cost-per-hour arrangement. For those contracts in which risk has not been determined to transfer to the service provider, the Company initially records monthly payments as a deposit and then accounts for the underlying maintenance event when it occurs, in accordance with the Company’s maintenance accounting policy.

Certain of the Company’s aircraft lease agreements require the Company to pay maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. At lease inception and at each balance sheet date, the Company assesses whether the maintenance reserve payments required by its leases are substantively and contractually related to the maintenance of the leased asset. Maintenance reserve payments that are determined to be related to the maintenance of the leased asset are accounted for as maintenance deposits, to the extent they are expected to be recoverable, and are reflected as aircraft maintenance deposits on the Company’s consolidated balance sheets. When it is not probable that the Company will recover amounts currently on deposit with a lessor, such amounts are expensed as supplemental rent within aircraft rent in the Company’s consolidated statements of operations. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments and are not included within the right-of-use asset and respective lease liability.

The Company makes certain assumptions at the inception of the lease and at each balance sheet date to determine the recoverability of maintenance deposits. These assumptions are based on various factors, such as the estimated time between the maintenance events, the cost of such maintenance events, the date the aircraft is due to be returned to the lessor and the number of flight hours and cycles the aircraft is estimated to be utilized before it is returned to the lessor. Changes in estimates are accounted for on a cumulative catch-up basis. On a regular basis, the Company assesses the credit worthiness of the Company’s lessors to ensure deposits are collectible. The Company continues to evaluate the creditworthiness of its lessors as a result of the COVID-19 pandemic downturns and specifically whether any credit losses existed for aircraft maintenance deposits and determined no allowance was necessary as of December 31, 2021 and 2020.

Certain of the Company’s lease agreements provide that maintenance reserves held by the lessor at the expiration of the lease are nonrefundable to the Company and will be retained by the lessor. Consequently, any usage-based maintenance reserve payments after the last major maintenance event are not substantively related to the maintenance of the leased asset and, therefore, are accounted for as supplemental rent.

Leased Aircraft Return Costs

The Company’s aircraft lease agreements generally contain provisions that require the Company to return aircraft airframes and engines to the lessor in a specified condition or pay an amount to the lessor based on the airframe and engine’s actual return condition. Lease return costs include all costs that would be incurred at the return of the aircraft, including costs incurred to repair the airframe and engines to the condition required by the lease.

Lease return costs could include, but are not limited to, redelivery cost, redelivery crew cost, fuel, final inspections, reconfiguration of the cabin, repairs to the airframe, painting, overhaul of engines, replacement of components and checks. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost, there are various other factors which need to be considered such as current condition of the aircraft, the age of the aircraft at lease expiration, number of hours run on the engines, number of cycles run on the airframe, projected number of hours run on the engine at the time of return, the projected number of cycles run on the airframe at the time of return, the extent of repairs needed, if any, upon return, return locations, current configuration of the aircraft, current paint of the aircraft, estimated escalation of cost of repairs and materials at the time of return, current flight hour agreement rates and future flight hour agreement rates. In addition, typically near the lease return date, the lessors may allow maintenance reserves to be applied as return condition consideration or pass on certain return provisions if they do not align with their current plans to remarket the aircraft. As a result of the different factors listed above, management assesses the need to accrue lease return costs throughout the lease as facts and circumstances warrant an assessment. When costs become both probable and estimable, lease return costs are expensed as a component of aircraft rent in the consolidated statements of operations through the remaining lease term.

Derivative Instruments

Fuel Hedging Activities

Variability in jet fuel prices impacts the Company’s results of operations. In order to reduce the risk of exposure to fuel price increases, the Company may enter into derivative contracts such as swaps, call options and collars. Derivative instruments are stated at fair value, net of any collateral postings.

The Company formally designates and accounts for the derivative instruments that meet established accounting criteria under ASC 815, Derivatives and Hedging, as cash flow hedges. For derivative instruments that are designated and qualify as cash flow hedges, the gain or loss on the derivative instruments is recorded in accumulated other comprehensive income/loss (“AOCI/L”), a component of stockholders’ equity on the consolidated balance sheets. In general, the Company recognizes the associated gains or losses deferred in AOCI/L as a component of aircraft fuel expense within the consolidated statements of operations in the period that the aircraft fuel is consumed. For derivative instruments that are not designated as cash flow hedges, the gain or loss on the instrument is recognized in current period earnings. The Company presents its fuel derivative instruments net on the consolidated balance sheets. Refer to Note 7 for additional information regarding the Company’s hedge accounting and derivative instruments.

Aircraft Purchase Hedging ActivitiesThe Company is party to certain interest rate swaption agreements that are accounted for as cash flow hedges, as defined under ASC 815, Derivatives and Hedging. Some of the Company’s aircraft purchase commitments can expose it to interest rate risk as, depending on the agreement, rental payments are adjusted and become fixed based on the seven or nine year swap rate at the time of delivery. The primary objective for interest rate derivatives is to hedge the portion of the estimated future monthly rental payments related to the associated agreement’s variable interest rate, historically London Interbank Offered Rate (“LIBOR”). These swaption agreements provide for a single payment at maturity based upon the change in the applicable swap rate between the execution date and the termination date. For derivative instruments that are designated and qualify as cash flow hedges, the gain or loss on the derivative instruments is recorded in AOCI/L. In general, the Company recognizes the associated gains or losses deferred in AOCI/L as a component of aircraft rent expense in the Company’s consolidated statements of operations over the life of the lease on a straight-line basis. The Company presents its interest rate swaption derivative instruments net on the consolidated balance sheets.

Aircraft Fuel

Aircraft FuelAircraft fuel expense includes jet fuel and associated into-plane costs, federal and state taxes and the amortized gains, losses and premiums associated with effective fuel hedge contracts within AOCI/L and gains and losses from ineffective or dedesignated fuel hedge contracts.

Sales and Marketing

Sales and MarketingSales and marketing expense includes credit card processing fees, system booking fees, sponsorship and distribution costs such as the costs of the Company’s call center and advertising costs. Advertising and the related production costs are expensed as incurred

Income Taxes

Income TaxesThe Company accounts for income taxes using the asset and liability method. Deferred income taxes are recognized for the tax consequences of temporary differences between the tax and financial statement reporting bases of assets and liabilities. The Company periodically assesses whether it is more likely than not that sufficient taxable income will be generated to realize deferred income tax assets, and a valuation allowance is established if it is not likely that deferred income tax assets will be realized. The Company considers sources of taxable income from prior period carryback periods, future reversals of existing taxable temporary differences, tax planning strategies and future projected taxable income when assessing the future realization of deferred tax assets. In assessing the sources of income and the need for a valuation allowance, the Company considers all available positive and negative evidence, which includes a recent history of cumulative losses.

Stock-Based Compensation

The Company recognizes cost of employee services received in exchange for awards of equity instruments based on the fair value of each instrument at the date of grant. Compensation expense is recognized over the period during which an employee is required to provide service in exchange for an award, with forfeitures accounted for as they occur. The fair value of stock option awards is estimated on the date of grant using the Black-Scholes valuation

model. Restricted stock awards and units are valued at the fair value of the shares on the date of grant. The exercise price of all stock awards is determined by the Company’s board of directors based, in part, on the ending stock price on the grant date. Prior to the Company’s IPO, there were significant judgments and estimates inherent in these valuations which included assumptions regarding the Company’s future operating performance, the time to complete potential liquidity events and the determinations of the appropriate valuation methods to be applied.

Recently Adopted Accounting Pronouncements

standard was adopted using the modified retrospective approach with an effective date as of the beginning of the Company’s fiscal year, January 1, 2019. See Note 10 for more information.

Revenue from contract with customer

Passenger Revenues

Fare revenues. Tickets sold in advance of the flight date are initially recorded as an air traffic liability on the Company’s consolidated balance sheets. Fare revenues are recognized in passenger revenues within the consolidated statements of operations at the time of departure when transportation is provided.

As of December 31, 2020, the Company’s current air traffic liability balance was $135 million. During the year ended December 31, 2021, 89% of the air traffic liability as of December 31, 2020 has been recognized as passenger revenue within the consolidated statements of operations. As of December 31, 2021, the Company’s current air traffic liability is $273 million, of which $59 million is related to customer rights to book future travel, which either expire within 3 or 12 months after issuance if not redeemed by the customer. The amounts expected not to be redeemed are recognized over the historical pattern of rights exercised by customers to fare revenues in passenger revenues within the consolidated statements of operations.

During the years ended December 31, 2021, 2020 and 2019, the Company recognized $58 million, $126 million and $26 million of revenue, respectively, in passenger revenues within the consolidated statements of operations, primarily related to expected and actual expiration of customer rights to book future travel. Estimated and actual expiration of customer rights to book future travel during the year ended December 31, 2020 was mainly due to the large amount of modifications of travel initiated by customers during late March through June 30, 2020 as a result of the COVID-19 pandemic.

Non-fare passenger revenues. Certain ancillary items such as service fees, baggage and seat selection deemed part of providing passenger transportation are recognized to non-fare passenger revenues in passenger revenues within the consolidated statements of operations. Service fees include, among other things, convenience fees, charges for nonrefundable ticket expiration, cancellation charges and service charges assessed for itinerary changes made prior to the date of departure. Such change fees are recognized at the time of departure of the newly scheduled travel. Beginning in March 2020, resulting from the reduction in demand from the COVID-19 pandemic, the Company waived cancellation and change fees for customers for most of 2020 and the first quarter of 2021.

Passenger Taxes and Fees. The Company is required to collect certain taxes and fees from customers on behalf of government agencies and airports and remit these back to the applicable governmental entity or airport on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, airport passenger facility charges, and foreign arrival and departure taxes. These taxes and fees are collected from customers at the time they purchase their tickets but are not included in passenger revenues at that time. The Company records a liability upon collection from the customer and reduces the liability when payments are remitted to the applicable governmental agency or airport.

Other Revenues

Other revenues primarily consists of services not directly related to providing transportation, such as the advertising, marketing and brand elements of the Frontier Miles affinity credit card program and commissions revenue from the third-party sale of items such as rental cars and hotels.

Frequent Flyer Program

The Company’s Frontier Miles frequent flyer program provides frequent flyer travel awards to program members based on accumulated mileage credits. Mileage credits are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for mileage credits earned by passengers under its Frontier Miles program based on the equivalent ticket value (“ETV”) a passenger receives by redeeming mileage credits for a ticket rather than paying cash.

Mileage credits are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have three separate performance obligations: (i) mileage credits to be awarded, (ii) licensing of brand and access to member lists and (iii) advertising and marketing efforts. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For mileage credits, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of mileage credits needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace and industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation, the Company considers market-specific factors and entity-specific factors, including the Company’s internal costs of providing services, volume of marketing efforts and overall advertising plan.

Consideration allocated based on the relative standalone selling price to both the brand licensing and access to member lists and advertising and marketing elements is recognized as other revenue in the Company’s consolidated statements of operations over time as mileage credits are delivered. The consideration allocated to the transportation portion of these mileage credit sales is deferred and recognized as a component of passenger revenue in the Company’s consolidated statements of operations at the time of travel for mileage credits redeemed. Mileage credits that the Company estimates are not likely to be redeemed are subject to breakage and are recognized as a portion of passenger revenues in the Company’s consolidated statements of operations in proportion to the pattern of rights exercised by customers. Management uses statistical models to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which mileage credits are expected to be redeemed, the actual redemption activity for mileage credits or the estimated fair value of mileage credits expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years. Redemptions are allocated between sold and flown mileage credits based on historical patterns. As a result of the reduction in demand due to the COVID-19 pandemic, beginning in March 2020, the Company extended the expiration dates of mileage credits issued under its frequent flyer program.

During September 2020, the Company amended its credit card affinity agreement with its credit card partner Barclays. The amended and restated agreement, similar to the previous arrangement, provides for joint marketing, grants certain benefits to co-branded credit card holders, and allows Barclays to market using the Company’s customer database. Cardholders earn mileage credits under the Frontier Miles program and the Company sells mileage credits at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers. The amended and restated agreement extended the term from 2023 to 2029 and provided for an up-front non-refundable payment of $25 million to the Company, of which the unamortized portion is recorded within other current liabilities, other long-term liabilities, and long-term frequent flyer liability on the consolidated balance sheets. The non-refundable payment will be recognized as other revenue

in the Company’s consolidated statements of operations over the contact period as the Company performs its performance obligations under the amended agreement.

Gains on Sale-Leaseback Transactions

Gains on Sale-Leaseback TransactionsThe Company enters into sale-leaseback transactions for its aircraft and aircraft engine assets, whereby the Company sells one or more aircraft or aircraft engine assets to a third-party and simultaneously enters into an operating lease for a right to use such assets for a fixed period of time. Gains on sale-leaseback transactions are recognized in the period in which title to the asset transfers to the buyer-lessor and the lease commences, as a component of other operating expenses within the consolidated statements of operations. Gains on sale-leaseback transactions are calculated as the excess of the sale price of the asset over its carrying value. The carrying value of the assets sold will generally include the price paid for the asset, net of the amount of cash or the fair value of non-cash credits and incentives received from equipment and component manufacturers, the costs associated with delivery of the asset including any taxes or tariffs, financing costs capitalized in connection with the construction of the asset, capitalized maintenance and other improvements, and accumulated depreciation. Gains on sale-leaseback transactions may also be adjusted if it is determined that the terms of the sale transaction or the lease agreement are at a price other than fair value.

Fair Value Measurement

Under ASC 820, Fair Value Measurements and Disclosures, disclosures relating to how fair value is determined for assets and liabilities are required, and a hierarchy for which these assets and liabilities must be grouped is established, based on significant levels of inputs, as follows:

Level 1—Quoted prices in active markets for identical assets or liabilities.

Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes several valuation techniques in order to assess the fair value of its financial assets and liabilities.

Cash, Cash Equivalents and Restricted Cash

Cash and cash equivalents are comprised of liquid money market funds, time deposits and cash and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value.

Warrants

The estimated fair value of the warrants issued in conjunction with the loans from the CARES Act, described in Note 2, was previously determined to be Level 3 measurement as of December 31, 2020. As a result of the Company’s IPO, the Company has the intent and ability to settle the warrants issued to the Treasury in shares and thus, as of April 6, 2021, the Company reclassified the warrant liability to additional paid-in capital on the consolidated balance sheet. Subsequent warrants issued after the IPO date were recorded at fair value as a reduction to the related debt they were issued with and recorded to additional paid-in capital on the consolidated balance sheet. As the warrants issued under the CARES Act will no longer be subject to recurring fair value measurements, they have been excluded from the table below as of December 31, 2021.

Debt

The estimated fair value of the Company’s debt agreements has been determined to be Level 3 measurement, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes a discounted cash flow method to estimate the fair value of the Level 3 long-term debt.

Operating Leases

The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related operating lease right-of-use asset and corresponding operating lease liability are recorded at the present value of lease payments over the term on the Company’s consolidated balance sheets. Some leases include rental escalation clauses, renewal options, termination options, and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components.

When available, the rate implicit in the lease is used to discount lease payments to present value; however, most leases do not provide a readily determinable implicit rate. Therefore, the Company estimates its incremental borrowing rate (“IBR”) to discount the lease payments based on information available at lease commencement. The IBR utilized by the Company is first determined using an unsecured recourse borrowing rate over a tenor that matches the period of lease payments for each individual lease and then is adjusted to arrive at a rate that is representative of a collateralized rate (secured rate). Given the Company does not have an established unsecured public credit rating, the Company utilizes current period and projected financial information to simulate an unsecured credit rating. The Company then determines its secured rate (IBR) using a combination of several valuation methods that take into account the lower amount of risk of collateralized borrowings along with observable implied credit ratings from its current outstanding secured debt obligations.