New Accounting Pronouncements (Policies)	3 Months Ended
Mar. 31, 2025
Accounting Standards Update and Change in Accounting Principle [Abstract]
Basis of Presentation	The accompanying unaudited Condensed Consolidated Financial Statements of the Company and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles in the United States ("GAAP") for complete financial statements. The unaudited Condensed Consolidated Financial Statements for the interim periods ended March 31, 2025 and 2024 include all adjustments which are, in the opinion of management, necessary for a fair presentation of the results for the interim periods. This includes all normal and recurring adjustments and elimination of significant intercompany transactions. Financial results for the Company and airlines in general can be seasonal in nature. For example, absent other factors, travel demand is generally higher during the summer period, or the Company’s second and third fiscal quarters. However, air travel is also significantly impacted by general economic conditions, the amount of disposable income available to consumers and changes in consumer behavior, unemployment levels, corporate travel budgets, global pandemics, extreme or severe weather and natural disasters, fears of terrorism or war, governmental actions, and other factors beyond the Company's control. These and other factors, such as the price of jet fuel in some periods, the nature of the Company's fuel hedging program, and the periodic volatility of commodities used by the Company for hedging jet fuel, have created, and may continue to create, significant volatility in the Company's financial results. See Note 3 for further information on fuel and the Company's fuel hedging program. Operating results for the three months ended March 31, 2025, are not necessarily indicative of the results that may be expected for future quarters or for the year ended December 31, 2025. For further information, refer to the Consolidated Financial Statements and footnotes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2024.
Operating Segments and Related Disclosures	The Company's chief operating decision maker, the Company's President, Chief Executive Officer, & Vice Chairman of the Board of Directors, assesses performance for the Company's single reportable segment and decides how to allocate resources based on its Net income or loss (see the unaudited Condensed Consolidated Statement of Comprehensive Loss). For single reportable segment-level financial information, total assets, revenues from external customers, depreciation and amortization expense, interest income and interest expense, provision for income taxes, other non-operating expenses, and significant non-cash transactions,
New Accounting Pronouncements	On November 4, 2024, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This standard responds to investor input by requiring public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the notes to the financial statements. This standard is effective for all entities that are subject to Subtopic 220-40, for annual periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027, but early adoption is permitted. The Company is evaluating this new standard but does not expect it to have a significant impact on its financial statement disclosures. On December 14, 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This standard increases transparency and decision usefulness of income tax disclosures for investors by requiring information to better assess how an entity's operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. This standard requires entities to provide enhanced disclosures related to the income tax rate reconciliation and income taxes paid. This standard is effective for all entities that are subject to Topic 740, Income Taxes for annual periods beginning after December 15, 2024, but early adoption is permitted. The Company has evaluated this new standard and does not expect it to have a significant impact on its financial statement disclosures. The Company will include all required disclosures within its Form 10-K for the year ended December 31, 2025, utilizing the retrospective application as permitted in the standard.
Financial Derivative Instruments	The Company has used financial derivative instruments for both short-term and long-term timeframes, and historically has used a mixture of purchased call options, collar structures (which include both a purchased call option and a sold put option), call spreads (which include a purchased call option and a sold call option), put spreads (which include a purchased put option and a sold put option), and fixed price swap agreements in its portfolio. The Company does not purchase or hold any financial derivative instruments for trading or speculative purposes. For the purpose of evaluating its net cash spend for jet fuel and for forecasting its future estimated jet fuel expense, the Company evaluates its hedge volumes strictly from an "economic" standpoint and, thus, does not consider whether the hedges have qualified or will qualify for hedge accounting. The Company defines its "economic" hedge as the net volume of fuel derivative contracts held, including the impact of positions that have been offset through sold positions, regardless of whether those contracts qualify for hedge accounting. The level at which the Company is economically hedged for a particular period is also dependent on current market prices for that period, as well as the types of derivative instruments held and the strike prices of those instruments. For example, the Company has entered into "out-of-the-money" option contracts (including "catastrophic" protection, which the Company defines as prices significantly higher than historical average levels), which may not generate intrinsic gains at settlement if market prices do not rise above the option strike price. Therefore, even though the Company may have an economic hedge in place for a particular period, that hedge may not produce any hedging gains at settlement and may even produce hedging losses depending on market prices, the types of instruments held, and the strike prices of those instruments. Upon proper qualification, the Company accounts for its fuel derivative instruments as cash flow hedges. Qualification is re-evaluated quarterly, and all periodic changes in fair value of the derivatives designated as hedges are recorded in Accumulated other comprehensive income ("AOCI") until the underlying jet fuel is consumed. See Note 4. When the Company has sold derivative positions in order to effectively "close" or offset a derivative already held as part of its fuel hedging portfolio, any subsequent changes in fair value of those positions are marked to market through the unaudited Condensed Consolidated Statement of Comprehensive Loss. Likewise, any changes in fair value of those positions that were offset by entering into the sold positions and were de-designated as hedges are concurrently marked to market through the unaudited Condensed Consolidated Statement of Comprehensive Loss. However, any changes in value related to hedges that were deferred as part of AOCI while designated as a hedge would remain until the originally forecasted transaction occurs. In a situation where it becomes probable that a fuel hedged forecasted transaction will not occur, any gains and/or losses that have been recorded to AOCI would be required to be immediately reclassified into the unaudited Condensed Consolidated Statement of Comprehensive Loss. In some situations, an entire commodity type used in hedging may cease to qualify for special hedge accounting treatment. As an example, in certain prior periods, the Company's routine statistical analysis performed to determine which commodities qualified for special hedge accounting treatment on a prospective basis indicated that West Texas Intermediate ("WTI") crude oil-based derivatives no longer qualified for hedge accounting, and therefore the Company could no longer demonstrate that derivatives based on WTI crude oil prices would result in effective hedges on a prospective basis. As such, all WTI-based instruments were de-designated from their hedging relationships, and the changes in fair value of all of the Company's derivatives based in WTI were recorded directly to Other (gains) losses on a prospective basis. The Company's routine statistical analysis performed for the three months ended March 31, 2025, indicated that all commodities currently being utilized by the Company qualify for hedge accounting. All of the Company's fuel derivative instruments are subject to agreements that follow the netting guidance in the applicable accounting standards for derivatives and hedging. The types of derivative instruments the Company has determined are subject to netting requirements in the accompanying unaudited Condensed Consolidated Balance Sheet are those in which the Company pays or receives cash for transactions with the same counterparty and in the same currency via one net payment or receipt. For cash collateral held by the Company or provided to counterparties, the Company nets such amounts against the fair value of the Company's derivative portfolio by each counterparty. The Company has elected to utilize netting for its fuel derivative instruments and also classifies such amounts as either current or noncurrent, based on the net fair value position with each of the Company's counterparties in the unaudited Condensed Consolidated Balance Sheet. If the Company's fuel derivative instruments are in a net asset position with a counterparty, cash collateral amounts held are first netted against current outstanding derivative asset amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of noncurrent outstanding fuel derivative instruments. The Company is at times party to certain interest rate swap agreements that are accounted for as cash flow hedges, but had none in place as of March 31, 2025, or as of December 31, 2024. The Company also did not have any interest rate swap agreements designated as fair value hedges, as defined, during the periods presented.
Revenue	The Company’s contracts with its Customers primarily consist of its tickets sold, which are initially deferred as Air traffic liability. Passenger revenue associated with tickets is recognized when the performance obligation to the Customer is satisfied, which is primarily when travel is provided. For air travel on Southwest, the amount of tickets (which includes flight credits—also referred to as partial tickets) that will go unused, referred to as breakage, is estimated and recognized in Passenger revenue once the scheduled flight date has passed. Revenue is categorized by revenue source as the Company believes it best depicts the nature, amount, timing, and uncertainty of revenue and cash flow. Under the Company's current policy, flight credits never expire. However, as the Company believes that a portion of Customer flight credits issued will not be redeemed, it estimates and records breakage associated with such amounts. Customer flight credits represent approximately 7 percent and 8 percent of the total Air traffic liability balance as of March 31, 2025, and December 31, 2024, respectively. On March 11, 2025, the Company announced a change to its flight credit policy. Flight credits issued for reservations booked and ticketed or changed on or after May 28, 2025, will have a specified expiration date. The Company recognizes revenue related to the marketing, advertising, and other travel-related benefits of the cash receipts associated with various loyalty partner agreements including, but not limited to, its co-branded credit card agreement with Chase Bank USA, N.A. (“Chase”). For the three months ended March 31, 2025 and 2024, the Company recognized $569 million and $542 million of such revenue, respectively, the majority of which is within Other operating revenues. Through the co-branded credit card agreement with Chase, the Company sells loyalty points, certain marketing benefits, which consist of the use of the Southwest Airlines brand and access to Rapid Rewards Member lists, licensing and advertising elements, and the use of the Company’s resource team, and other airline benefits. The Company allocates consideration received to performance obligations based on the relative fair value of those obligations. In first quarter 2025, the Company and Chase executed an amendment to the co-branded credit card agreement that extended the term of the agreement and added enhanced airline benefits for Cardmembers associated with the Company's planned assigned and premium seating initiative. The Company estimated the selling prices and volumes over the term of the amended agreement in order to determine the allocation of proceeds to each of the three performance obligations identified in the agreement, which have been characterized as a transportation component, a marketing component, and an airline benefits component. The Company records Passenger revenue related to loyalty point redemptions for air travel when the travel is delivered, the marketing elements are recognized as Other revenue when the performance obligations related to those services are satisfied, which is generally the same period consideration is received from Chase, and the airline benefits are recognized as Passenger revenue when they are provided.
Fair Value Measurements	Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. As of March 31, 2025, the Company held certain items that are required to be measured at fair value on a recurring basis. These included cash equivalents, short-term investments, fuel derivative contracts, and available-for-sale securities. The majority of the Company’s cash equivalents and short-term investments consist of instruments classified as Level 1. However, the Company has certificates of deposit, commercial paper, and time deposits that are classified as Level 2, due to the fact that the fair value for these instruments is determined utilizing observable inputs in non-active markets. Equity securities primarily consist of investments with readily determinable market values associated with the Company’s excess benefit plan. The Company’s derivative instruments consist of over-the-counter contracts, which are not traded on a public exchange. Fuel derivative instruments currently consist solely of option contracts, whereas interest rate derivatives have historically consisted solely of swap agreements. See Note 3 for further information on the Company’s derivative instruments and hedging activities. The Company determines the value of option contracts utilizing an option pricing model based on inputs that are either readily available in public markets, can be derived from information available in publicly quoted markets, or are provided by financial institutions that trade these contracts. The option pricing model used by the Company is an industry standard model for valuing options and is a similar model used by the broker/dealer community (i.e., the Company’s counterparties). The inputs to this option pricing model are the option strike price, underlying price, risk free rate of interest, time to expiration, and volatility. Because certain inputs used to determine the fair value of option contracts are unobservable (principally implied volatility), the Company has categorized these option contracts as Level 3. Volatility information is obtained from external sources, but is analyzed by the Company for reasonableness and compared to similar information received from other external sources. The fair value of option contracts considers both the intrinsic value and any remaining time value associated with those derivatives that have not yet settled. The Company also considers counterparty credit risk and its own credit risk in its determination of all estimated fair values. To validate the reasonableness of the Company’s option pricing model, on a monthly basis, the Company compares its option valuations to third party valuations. If any significant differences were to be noted, they would be researched in order to determine the reason. However, historically, no significant differences have been noted. The Company has consistently applied these valuation techniques in all periods presented and believes it has obtained the most accurate information available for the types of derivative contracts it holds. Included in Equity securities are the Company’s investments primarily associated with its deferred compensation plans, which consist of mutual funds that are publicly traded and for which market prices are readily available. These plans are non-qualified deferred compensation plans designed to hold contributions in excess of limits established by the Internal Revenue Code of 1986, as amended. The distribution timing and payment amounts under these plans are made based on the participant’s distribution election and plan balance. Assets related to the funded portions of the deferred compensation plans are held in a rabbi trust, and the Company remains liable to these participants for the unfunded portion of the plans. The Company records changes in the fair value of plan obligations and plan assets, which net to zero, within the Salaries, wages, and benefits line and Other (gains) losses, net line, respectively, of the unaudited Condensed Consolidated Statement of Comprehensive Loss.

New Accounting Pronouncements (Policies)

3 Months Ended

Mar. 31, 2025

Accounting Standards Update and Change in Accounting Principle [Abstract]

The accompanying unaudited Condensed Consolidated Financial Statements of the Company and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles in the United States ("GAAP") for complete financial statements. The unaudited Condensed Consolidated Financial Statements for the interim periods ended March 31, 2025 and 2024 include all adjustments which are, in the opinion of management, necessary for a fair presentation of the results for the interim periods. This includes all normal and recurring adjustments and elimination of significant intercompany transactions. Financial results for the Company and airlines in general can be seasonal in nature. For example, absent other factors, travel demand is generally higher during the summer period, or the Company’s second and third fiscal quarters. However, air travel is also significantly impacted by general economic conditions, the amount of disposable income available to consumers and changes in consumer behavior, unemployment levels, corporate travel budgets, global pandemics, extreme or severe weather and natural disasters, fears of terrorism or war, governmental actions, and other factors beyond the Company's control. These and other factors, such as the price of jet fuel in some periods, the nature of the Company's fuel hedging program, and the periodic volatility of commodities used by the Company for hedging jet fuel, have created, and may continue to create, significant volatility in the Company's financial results. See Note 3 for further information on fuel and the Company's fuel hedging program. Operating results for the three months ended March 31, 2025, are not necessarily indicative of the results that may be expected for future quarters or for the year ended December 31, 2025. For further information, refer to the Consolidated Financial Statements and footnotes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2024.

Operating Segments and Related Disclosures

The Company's chief operating decision maker, the Company's President, Chief Executive Officer, & Vice Chairman of the Board of Directors, assesses performance for the Company's single reportable segment and decides how to allocate resources based on its Net income or loss (see the unaudited Condensed Consolidated Statement of Comprehensive Loss).

For single reportable segment-level financial information, total assets, revenues from external customers, depreciation and amortization expense, interest income and interest expense, provision for income taxes, other non-operating expenses, and significant non-cash transactions,

New Accounting Pronouncements

On November 4, 2024, the Financial Accounting Standards Board (the "FASB") issued Accounting Standards Update ("ASU") 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This standard responds to investor input by requiring public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the notes to the financial statements. This standard is effective for all entities that are subject to Subtopic 220-40, for annual periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027, but early adoption is permitted. The Company is evaluating this new standard but does not expect it to have a significant impact on its financial statement disclosures.

On December 14, 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This standard increases transparency and decision usefulness of income tax disclosures for investors by requiring information to better assess how an entity's operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. This standard requires entities to provide enhanced disclosures related to the income tax rate reconciliation and income taxes paid. This standard is effective for all entities that are subject to Topic 740, Income Taxes for annual periods beginning after December 15, 2024, but early adoption is permitted. The Company has evaluated this new standard and does not expect it to have a significant impact on its financial statement disclosures. The Company will include all required disclosures within its Form 10-K for the year ended December 31, 2025, utilizing the retrospective application as permitted in the standard.

Financial Derivative Instruments

The Company has used financial derivative instruments for both short-term and long-term timeframes, and historically has used a mixture of purchased call options, collar structures (which include both a purchased call option and a sold put option), call spreads (which include a purchased call option and a sold call option), put spreads (which include a purchased put option and a sold put option), and fixed price swap agreements in its portfolio. The Company does not purchase or hold any financial derivative instruments for trading or speculative purposes.

For the purpose of evaluating its net cash spend for jet fuel and for forecasting its future estimated jet fuel expense, the Company evaluates its hedge volumes strictly from an "economic" standpoint and, thus, does not consider whether the hedges have qualified or will qualify for hedge accounting. The Company defines its "economic" hedge as the net volume of fuel derivative contracts held, including the impact of positions that have been offset through sold positions, regardless of whether those contracts qualify for hedge accounting. The level at which the Company is economically hedged for a particular period is also dependent on current market prices for that period, as well as the types of derivative instruments held and the strike prices of those instruments. For example, the Company has entered into "out-of-the-money" option contracts (including "catastrophic" protection, which the Company defines as prices significantly higher than historical average levels), which may not generate intrinsic gains at settlement if market prices do not rise above the option strike price. Therefore, even though the Company may have an economic hedge in place for a particular period, that hedge may not produce any hedging gains at settlement and may even produce hedging losses depending on market prices, the types of instruments held, and the strike prices of those instruments.

Upon proper qualification, the Company accounts for its fuel derivative instruments as cash flow hedges. Qualification is re-evaluated quarterly, and all periodic changes in fair value of the derivatives designated as hedges are recorded in Accumulated other comprehensive income ("AOCI") until the underlying jet fuel is consumed. See Note 4.

When the Company has sold derivative positions in order to effectively "close" or offset a derivative already held as part of its fuel hedging portfolio, any subsequent changes in fair value of those positions are marked to market through the unaudited Condensed Consolidated Statement of Comprehensive Loss. Likewise, any changes in fair value of those positions that were offset by entering into the sold positions and were de-designated as hedges are concurrently marked to market through the unaudited Condensed Consolidated Statement of Comprehensive Loss. However, any changes in value related to hedges that were deferred as part of AOCI while designated as a hedge would remain until the originally forecasted transaction occurs. In a situation where it becomes probable that a fuel hedged forecasted transaction will not occur, any gains and/or losses that have been recorded to AOCI would be required to be immediately reclassified into the unaudited Condensed Consolidated Statement of Comprehensive Loss.

In some situations, an entire commodity type used in hedging may cease to qualify for special hedge accounting treatment. As an example, in certain prior periods, the Company's routine statistical analysis performed to determine which commodities qualified for special hedge accounting treatment on a prospective basis indicated that West Texas Intermediate ("WTI") crude oil-based derivatives no longer qualified for hedge accounting, and therefore the Company could no longer demonstrate that derivatives based on WTI crude oil prices would result in effective hedges on a prospective basis. As such, all WTI-based instruments were de-designated from their hedging relationships, and the changes in fair value of all of the Company's derivatives based in WTI were recorded directly to Other (gains) losses on a prospective basis. The Company's routine statistical analysis performed for the three months ended March 31, 2025, indicated that all commodities currently being utilized by the Company qualify for hedge accounting.

All of the Company's fuel derivative instruments are subject to agreements that follow the netting guidance in the applicable accounting standards for derivatives and hedging. The types of derivative instruments the Company has determined are subject to netting requirements in the accompanying unaudited Condensed Consolidated Balance Sheet are those in which the Company pays or receives cash for transactions with the same counterparty and in the same currency via one net payment or receipt. For cash collateral held by the Company or provided to counterparties, the Company nets such amounts against the fair value of the Company's derivative portfolio by each counterparty. The Company has elected to utilize netting for its fuel derivative instruments and also classifies such amounts as either current or noncurrent, based on the net fair value position with each of the Company's counterparties in the unaudited Condensed Consolidated Balance Sheet. If the Company's fuel derivative instruments are in a net asset position with a counterparty, cash collateral amounts held are first netted against current outstanding derivative asset amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of noncurrent outstanding fuel derivative instruments.

The Company is at times party to certain interest rate swap agreements that are accounted for as cash flow hedges, but had none in place as of March 31, 2025, or as of December 31, 2024. The Company also did not have any interest rate swap agreements designated as fair value hedges, as defined, during the periods presented.

Revenue

The Company’s contracts with its Customers primarily consist of its tickets sold, which are initially deferred as Air traffic liability. Passenger revenue associated with tickets is recognized when the performance obligation to the Customer is satisfied, which is primarily when travel is provided. For air travel on Southwest, the amount of tickets (which includes flight credits—also referred to as partial tickets) that will go unused, referred to as breakage, is estimated and recognized in Passenger revenue once the scheduled flight date has passed.

Revenue is categorized by revenue source as the Company believes it best depicts the nature, amount, timing, and uncertainty of revenue and cash flow.

Under the Company's current policy, flight credits never expire. However, as the Company believes that a portion of Customer flight credits issued will not be redeemed, it estimates and records breakage associated with such amounts. Customer flight credits represent approximately 7 percent and 8 percent of the total Air traffic liability balance as of March 31, 2025, and December 31, 2024, respectively. On March 11, 2025, the Company announced a change to its flight credit policy. Flight credits issued for reservations booked and ticketed or changed on or after May 28, 2025, will have a specified expiration date.

The Company recognizes revenue related to the marketing, advertising, and other travel-related benefits of the cash receipts associated with various loyalty partner agreements including, but not limited to, its co-branded credit card agreement with Chase Bank USA, N.A. (“Chase”). For the three months ended March 31, 2025 and 2024, the Company recognized $569 million and $542 million of such revenue, respectively, the majority of which is within Other operating revenues.

Through the co-branded credit card agreement with Chase, the Company sells loyalty points, certain marketing benefits, which consist of the use of the Southwest Airlines brand and access to Rapid Rewards Member lists, licensing and advertising elements, and the use of the Company’s resource team, and other airline benefits. The Company allocates consideration received to performance obligations based on the relative fair value of those obligations. In first quarter 2025, the Company and Chase executed an amendment to the co-branded credit card agreement that extended the term of the agreement and added enhanced airline benefits for Cardmembers associated with the Company's planned assigned and premium seating initiative. The Company estimated the selling prices and volumes over the term of the amended agreement in order to determine the allocation of proceeds to each of the three performance obligations identified in the agreement, which have been characterized as a transportation component, a marketing component, and an airline benefits component. The Company records Passenger revenue related to loyalty point redemptions for air travel when the travel is delivered, the marketing elements are recognized as Other revenue when the performance obligations related to those services are satisfied, which is generally the same period consideration is received from Chase, and the airline benefits are recognized as Passenger revenue when they are provided.

Fair Value Measurements

Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

As of March 31, 2025, the Company held certain items that are required to be measured at fair value on a recurring basis. These included cash equivalents, short-term investments, fuel derivative contracts, and available-for-sale securities. The majority of the Company’s cash equivalents and short-term investments consist of instruments classified as Level 1. However, the Company has certificates of deposit, commercial paper, and time deposits that are classified as Level 2, due to the fact that the fair value for these instruments is determined utilizing observable inputs in non-active markets. Equity securities primarily consist of investments with readily determinable market values associated with the Company’s excess benefit plan.

The Company’s derivative instruments consist of over-the-counter contracts, which are not traded on a public exchange. Fuel derivative instruments currently consist solely of option contracts, whereas interest rate derivatives have historically consisted solely of swap agreements. See Note 3 for further information on the Company’s derivative instruments and hedging activities. The Company determines the value of option contracts utilizing an option pricing model based on inputs that are either readily available in public markets, can be derived from information available in publicly quoted markets, or are provided by financial institutions that trade these contracts. The option pricing model used by the Company is an industry standard model for valuing options and is a similar model used by the broker/dealer community (i.e., the Company’s counterparties). The inputs to this option pricing model are the option strike price, underlying price, risk free rate of interest, time to expiration, and volatility. Because certain inputs used to determine the fair value of option contracts are unobservable (principally implied volatility), the Company has categorized these option contracts as Level 3. Volatility information is obtained from external sources, but is analyzed by the Company for reasonableness and compared to similar information received from other external sources. The fair value of option contracts considers both the intrinsic value and any remaining time value associated with those derivatives that have not yet settled. The Company also considers counterparty credit risk and its own credit risk in its determination of all estimated fair values. To validate the reasonableness of the Company’s option pricing model, on a monthly basis, the Company compares its option valuations to third party

valuations. If any significant differences were to be noted, they would be researched in order to determine the reason. However, historically, no significant differences have been noted. The Company has consistently applied these valuation techniques in all periods presented and believes it has obtained the most accurate information available for the types of derivative contracts it holds.

Included in Equity securities are the Company’s investments primarily associated with its deferred compensation plans, which consist of mutual funds that are publicly traded and for which market prices are readily available. These plans are non-qualified deferred compensation plans designed to hold contributions in excess of limits established by the Internal Revenue Code of 1986, as amended. The distribution timing and payment amounts under these plans are made based on the participant’s distribution election and plan balance. Assets related to the funded portions of the deferred compensation plans are held in a rabbi trust, and the Company remains liable to these participants for the unfunded portion of the plans. The Company records changes in the fair value of plan obligations and plan assets, which net to zero, within the Salaries, wages, and benefits line and Other (gains) losses, net line, respectively, of the unaudited Condensed Consolidated Statement of Comprehensive Loss.