Effective October 1, 2019, the Company adopted Topic 842 and recorded ROU assets and lease liabilities of $154.6 million and $141.9 million, respectively. As part of the adoption, prepaid aircraft rent, deferred rent credits and accrued aircraft rents of $35.8 million, $21.3 million and $1.8 million, respectively, were classified as a component of the Company’s ROU assets.

At March 31, 2020, the Company leased 18 aircraft, airport facilities, office space, and other property and equipment under non-cancelable operating leases. The leases require the Company to pay all taxes, maintenance, insurance, and other operating expenses. Rental expense is recognized on a straight-line basis over the lease term, net of lessor rebates and other incentives. The Company expects that, in the normal course of business, such operating leases that expire will be renewed or replaced by other leases, or the property may be purchased rather than leased. Aggregate rental expense under all operating aircraft, equipment and facility leases totaled approximately $18.6 million and $18.7 million for the three months ended March 31, 2020 and 2019, respectively, and $35.4 million and $37.8 million for the six months ended March 31, 2020 and 2019.

As of March 31, 2020, the Company’s operating lease right-of-use assets were $140.8 million, the Company’s current maturities of operating lease liabilities were $43.6 million, and the Company’s noncurrent lease liabilities were $78.7 million.

As of March 31, 2020, the Company’s operating lease payments in operating cash flows for the six months ended March 31, 2020 is $26.2 million. The disclosure is not applicable for the six months ended March 31, 2019 due to the method of adoption of the new leasing Standard ASC-842.⁽¹⁾

The table below presents lease related terms and discount rates as of March 31, 2020:

	Three Months Ended March 31,
	2020		2019		$ Change			% Change
Operating lease cost	$	18,583	$	18,714	$	(131	)		(0.7	)%


	Six Months Ended March 31,
	2020		2019		$ Change			% Change
Operating lease cost	$	35,366	$	37,804	$	(2,438	)		(6.4	)%

The following table summarizes future minimum rental payments primarily related to leased aircraft required under operating leases that had initial or remaining non-cancelable lease terms as of March 31, 2020 (in thousands):

Periods Ending March 31,	Total Maturities
2020	$	22,120
2021		46,777
2022		31,916
2023		14,547
2024		13,982
Thereafter		1,654
Less: Interest	$	(8,740	)
Amounts recorded in the Consolidated Balance Sheet	$	122,256

The following represents future minimum lease obligations under non-cancelable operating leases as of September 30, 2019 (in thousands):

Periods Ending September 30,	Total Payments
2020		47,814
2021		46,007
2022		31,090
2023		13,726
2024		13,185
Thereafter		1,368
Total	$	153,190

On March 26, 2020, the Company and General Electric Company (“GE”), acting through its GE-Aviation business unit, entered into (a) Amended and Restated Letter Agreement No. 13-1 (“Letter Agreement No. 13-1”), which amends and restates Letter Agreement No. 13 entered into by the parties effective December 11, 2019, and (b) Amended and Restated Letter Agreement No. 12-1 (“Letter Agreement No. 12-1” and together with Letter Agreement No. 13-1, the “Amended and Restated Letter Agreements”), which amends and restates Letter Agreement No. 12 entered into by the parties effective October 22, 2019. The Amended and Restated Letter Agreements each provide that they are effective March 20, 2020.

Under Letter Agreement No. 13-1, the Company has agreed to purchase and take delivery of 20 new spare CF34-8C5 engines. Delivery of the new spare engines will now commence in April 2021, with the final spare engine being delivered in December 2021. The parties had previously agreed to commence delivery of the new spare engines in August 2020. The payment terms for the new spare engines were also amended, with payments to now be made in four (4) separate tranches commencing in October and December 2020 and February and March 2021.

Under Letter Agreement No. 12-1, the Company has agreed to purchase and take delivery of two (2) new spare CF34-8C5 engines by no later than March 31, 2020. The parties agreed that progress payments previously made by the Company constitute full payment for these engines. The Company does not consider this Letter Agreement to be a material definitive agreement, as defined by the rules and regulations of the Securities and Exchange Commission, but has elected to voluntarily file such Letter Agreement along with the filing of Letter Agreement No. 13-1. The total purchase commitment under these agreements is approximately $118.9 million.

If the Company fails to accept delivery of the spare engines when duly tendered, the Company may be assessed a minimum cancellation charge based on the engine price determined as of the date of scheduled engine delivery to the Company.