At September 30, 2023, the Company leased 18 aircraft, airport facilities, office space, and other property and equipment under non-cancelable operating leases. The operating leases require the Company to pay 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 $12.2 million, $43.4 million, and $44.6 million for the year ended September 30, 2023, 2022, and 2021, respectively.

At September 30, 2023, the Company leased 15 aircraft and three spare engines under non-cancelable finance leases. Basic rent on finance leases is paid monthly and at the end of the lease term. At the end of the lease term, the Company has the option to purchase the aircraft and engines for most of the finance leases. These finance leases are reflected as finance lease obligations of $67.6 million on our consolidated balance sheet as of September 30, 2023.

The components of our operating and finance lease costs were as follows (in thousands):


	Year Ended September 30,
	2023		2022
Operating lease costs	$	8,517	$	37,637
Variable and short-term lease costs		3,691		5,783
Interest expense on finance lease liabilities		4,492	547
Amortization expense of finance lease assets		13,414		2,705
Total lease costs	$	30,114	$	46,672

As of September 30, 2023, the Company’s operating lease right-of-use assets were $9.7 million, the Company’s current maturities of operating lease liabilities were $3.5 million, and the Company’s noncurrent operating lease liabilities were $8.1 million. As of September 30, 2023, the Company’s current portion of finance lease liabilities were $57.7 million, and the Company’s noncurrent finance lease liabilities were $9.9 million.

The Company’s operating lease payments included in operating cash flows for the year ended September 30, 2023 and 2022 were approximately $9.5 million and $36.3 million, respectively. The Company’s finance lease interest payments included in operating cash flows for the year ended September 30, 2023 and 2022 were $1.2 million and $0.3 million, respectively. The Company’s finance lease principal payments included in financing cash flows for the year ended September 30, 2023 and 2022 were $15.1 million and $2.5 million, respectively.

To determine whether impairments exist for aircraft and other related assets used in operations, we group assets, including ROU assets, at the CPA or FSA level (i.e., the lowest level for which there are identifiable cash flows) and then estimate future cash flows based on projections of CPA or FSA, block hours, maintenance events, labor costs and other relevant factors. As all of our aircraft leases besides one with an insignificant value on our books are leased to us from United or DHL at nominal amounts and not recorded on our books, we did not assess leased aircraft for impairment. The Company recorded impairment losses of zero, $10.5 million, and zero for the years ended September 30, 2023, 2022, and 2021, respectively.

The table below presents the weighted average remaining terms and discount rates for our operating and finance leases as of September 30, 2023:


As of September 30, 2023
Finance leases:
Weighted average remaining lease term	2.17
Weighted average discount rate		3.4	%
Operating leases:
Weighted average remaining lease term	6.1
Weighted average discount rate		5.6	%

The following table summarizes future minimum rental payments, primarily related to leased aircraft, required under operating and finance leases that had initial or remaining non-cancelable lease terms as of September 30, 2023 (in thousands):


Periods Ending September 30,	Operating Leases			Finance Leases
2024	$	4,243		$	57,704
2025		2,449			1,257
2026		1,520			1,332
2027		1,437			1,411
2028		1,030			1,495
Thereafter		4,161			4,437
Total lease payments		14,840			67,636
Less: imputed interest		(3,253	)		—
Amounts recorded in the consolidated balance sheet	$	11,587		$	67,636

RASPRO Lease Facility. On September 23, 2005, Mesa Airlines, as lessee, entered into the RASPRO Lease Facility, with RASPRO as lessor, for 15 of our CRJ-900 aircraft. The obligations under the RASPRO Lease Facility are guaranteed by us, and basic rent is paid quarterly on each aircraft. On each of March 10, 2014, June 5, 2014, and December 8, 2017, the RASPRO Lease Facility was amended to defer certain payments of basic rent (the "Deferred Amounts"). Until the principal of and accrued interest on the Deferred Amounts are paid in full: (i) we and Mesa Airlines are prohibited from paying any dividends to holders of our common stock, (ii) we are prohibited from repurchasing any of our warrants or other equity interests, (iii) Mesa Airlines must maintain a minimum of $35.0 million of cash, cash equivalents and availability under lines of credit, (iv) Mesa Airlines must provide RASPRO with periodic monthly, quarterly and annual reports containing certain financial information and forecasted engine repair costs and (v) we must maintain a minimum debt-to-assets ratio.

In June 2020, the Company amended its RASPRO aircraft lease agreement to defer a $4.0 million lease payment otherwise due in June 2020. Per the amended agreement dated June 5, 2020, the Company is required to pay this amount over the period of September 2021 through March 2024. The Company made the accounting election available for COVID-19 related concessions provided by a lessor and accordingly, this was not a lease modification and required no changes to current accounting treatment.

In December 2022, the Company entered into an agreement with RASPRO Trust, reducing the buyout price on all 15 aircraft at lease termination by a total of $25 million. Under the terms of the new agreement, the Company reclassified these leases as finance leases.