Airline Operating Leases & Sale-Leaseback Transactions

What Aircraft Operating Leases Are

An airline operating lease is a contract under which an airline pays a lessor — typically an aircraft leasing company — for the right to operate an aircraft for a defined term, after which the aircraft is returned to the lessor. The airline does not acquire ownership of the aircraft at any point during the lease. The most common form is the "dry lease," in which the lessor provides only the aircraft; the airline supplies the crew, maintenance, and insurance.

According to AerCap's Q3 2025 Fact Sheet, approximately 50% of the world's commercial aircraft fleet is leased, and the fleet on operating lease has trebled in the past 20 years. A separate August 2025 industry analysis estimates 13,295 aircraft on lease out of a total fleet of 35,550 — a penetration rate of 37.3% — with the discrepancy reflecting differences in fleet definition and whether stored aircraft are included. In the United States, the leased share of airline fleets is estimated at 49%.

Long-term operating leases for narrowbody and widebody aircraft span 6 to 12 years in duration. Air Lease Corporation reported a weighted average remaining lease term of 7.2 years and a weighted average fleet age of 4.6 years across its 489-aircraft owned fleet as of December 31, 2024.

The Lessor Market

The six largest lessors by fleet size account for approximately 65% of the global leased aircraft market. AerCap, SMBC Aviation Capital, and Avolon collectively controlled approximately 30% of the global leased fleet in 2024. The lessor concentration data are sourced from Aerospace Global News and AvBench via AviationA2Z, as detailed in the table below.

Lessor	Owned Aircraft	Managed Aircraft	Total Fleet	Assets
AerCap	1,515	166	1,681	$72B (Q3 2025)
SMBC Aviation Capital	490	232	722	$15.9B
Avolon	601	36	637	$30.7B
BBAM	560	—	560	$22.9B
Air Lease Corporation	503	50	553	$19.5B
BOC Aviation	425	17	442	$30.2B

Source: Aerospace Global News, January 2026 (fleet); AvBench via AviationA2Z, January 2025 (asset values).

AerCap became the largest lessor after acquiring GE Capital Aviation Services (GECAS) in 2021. Over 90% of AerCap's aircraft on order are new-technology narrowbodies. BOC Aviation reported record profits of $924 million in 2024, a 21% increase over 2023, driven by fleet growth and higher lease rates.

Current Lease Rates

Aircraft lease rates are benchmarked by IBA Aero, which publishes monthly rate indices. As of September 2024:

Aircraft Type	Condition	Monthly Lease Rate
Airbus A320neo	New	~$400,000
Boeing 737 MAX 8	New	~$400,000
Airbus A321NX	New	~$460,000
Boeing 737-800 / Airbus A320	Mid-life	$230,000–$250,000
Boeing 787-9	New	~$1,050,000
Airbus A350-900	New	~$1,140,000
Boeing 777-300ER	12 years old	~$450,000

Lease rates for new-generation narrowbody aircraft increased through 2023 and 2024, driven by supply constraints from Boeing's production limitations and the Pratt & Whitney GTF engine inspection campaign, which grounded A320neo-family aircraft and forced operators to extend existing leases rather than return aircraft to the market. Aircraft production in 2024 was just over 1,100 units, falling short of 2023 levels and well below pre-pandemic production rates.

What a Sale-Leaseback Transaction Is

In a sale-leaseback (SLB), an airline sells an aircraft it owns — or an aircraft from its order book that has not yet been delivered — to a lessor, and simultaneously enters into an operating lease for the same aircraft. The airline receives cash at closing (the sale price) and makes periodic lease payments to the lessor for the duration of the lease term. The lessor acquires the aircraft as an investment asset and earns lease rental income.

For the airline, the SLB converts a capital asset into cash while preserving the use of the aircraft. For the lessor, it is an acquisition channel — an alternative to placing a direct order with Boeing or Airbus and then finding a lessee.

United Airlines executed multiple SLB transactions in 2025:

• 20 Boeing 737 MAX 9 aircraft with SMBC Aviation Capital (announced December 10, 2025), covering aircraft scheduled for delivery in 2025 and 2026. This was the third agreement between United and SMBC, following a lease of 20 Airbus A321neo aircraft and a prior SLB of 20 Boeing 737 MAX 8 aircraft.
• 10 Boeing 737 MAX 9 aircraft with Dubai Aerospace Enterprise (DAE) (announced July 2025), with deliveries from August 2025 through February 2026. United operates 104 Boeing 737 MAX 9 aircraft with an average age of three years and has 116 additional deliveries of the type on order.

United reported aircraft rent payments of $54 million in Q3 2025 (compared to $64 million in Q3 2024) and recognized gains of $75 million on "various aircraft sale-leaseback transactions" during Q3 2025.

Accounting Treatment Under ASC 842

The Financial Accounting Standards Board's ASC 842 (effective for public companies beginning in fiscal years after December 15, 2018) requires all leases — including operating leases — to be recognized on the balance sheet as a right-of-use (ROU) asset and a corresponding lease liability. Prior to ASC 842, operating leases were off-balance-sheet — only the periodic rent expense appeared in the income statement.

Under ASC 842, the distinction between operating leases and finance leases (formerly "capital leases") is preserved, but both appear on the balance sheet:

• Operating lease: The lessee recognizes a single straight-line lease expense each period, similar to pre-ASC 842 rent expense. The ROU asset and liability are on the balance sheet, but the income statement treatment remains a single operating expense line.
• Finance lease: The lessee recognizes interest expense on the lease liability and amortization of the ROU asset separately — front-loading the total expense.

Under IFRS 16 (the international counterpart), there is no operating lease category for lessees; all leases are treated using finance lease mechanics.

For SLB transactions under ASC 842, gain or loss recognition depends on whether the transaction qualifies as a "sale." If the transfer of the aircraft meets the criteria for a sale under ASC 606 (revenue recognition), the airline derecognizes the asset and recognizes a gain or loss. If the transaction does not qualify as a sale — for example, if the leaseback is classified as a finance lease — the airline records it as a financing arrangement rather than a sale. Spirit Airlines disclosed in its Q1 2024 10-Q that of five SLB transactions completed in 2023, two resulted in operating leases (and the airline recorded a $1.7 million loss), while three were deemed "failed sale-leaseback transactions" and were classified as finance leases.

How Leased Versus Owned Fleets Appear in Financial Statements

Delta Air Lines' 2024 10-K illustrates the financial reporting of a mixed fleet. Delta reported 975 mainline aircraft: 812 owned, 53 under finance leases, and 110 under operating leases.

Delta's balance sheet as of December 31, 2024 showed:

Liability Category	Amount
Debt and finance lease obligations	$16.194B
Operating lease liabilities	$6.564B
Sale-leaseback financing liabilities	$1.835B
Adjusted debt (including all lease liabilities)	$24.619B

The $6.564 billion in operating lease liabilities includes both fleet leases and ground/facility leases (airport terminal space, maintenance facilities, office buildings). Delta separately disclosed fleet operating lease liabilities of $3.178 billion at year-end 2024, down from $3.778 billion at year-end 2023.

United Airlines, with 1,061 aircraft as of February 2026, reported total debt and finance lease obligations of $27.2 billion and operating lease ROU assets of $3.895 billion as of Q1 2024.

Why Airlines Choose Operating Leases and SLBs

The decision to lease versus own is driven by three quantifiable factors:

1. Capital Preservation

A new Boeing 737 MAX 8 has a list price of $117–121.6 million. Airlines receive discounts from list price, but the capital outlay for a 50-aircraft order is measured in billions. An SLB allows the airline to take delivery, sell the aircraft to a lessor, and redeploy the capital. United's SLB of 20 737 MAX 9 aircraft with SMBC is estimated at a total asset value in the "multi-billion dollar range" based on list price economics.

2. Balance Sheet Management

Although ASC 842 brought operating leases onto the balance sheet, the income statement treatment differs. Operating leases produce a single, straight-line expense classified as an operating cost. Finance leases and debt-financed ownership produce interest expense and depreciation, which flow through different line items and affect debt-to-equity ratios differently. Delta's reporting of $16.194 billion in debt and finance lease obligations versus $6.564 billion in operating lease liabilities shows the separation in practice.

3. Fleet Flexibility

At the end of an operating lease (typically 6–12 years), the airline returns the aircraft. It is not committed to the residual value risk of owning a 15- or 20-year-old aircraft. Air Lease Corporation's fleet — with a weighted average age of 4.6 years — illustrates the lessor's role as the entity that manages the second and third life of an aircraft through remarketing.

Implications for Airport Finance

Airline fleet financing decisions interact with airport financial structures through several channels:

Airline Creditworthiness and Airport Revenue Bonds

Airport revenue bond credit analysts evaluate airline financial health as part of the overall credit assessment. An airline with $24.6 billion in adjusted debt (Delta, 2024) carries fixed obligations that affect its ability to absorb cost increases, including rate increases at its hub and spoke airports. The shift from off-balance-sheet operating leases (pre-ASC 842) to on-balance-sheet recognition means that airline leverage ratios reported since 2019 are not directly comparable to pre-2019 figures without adjustment.

Airline Fleet Decisions and Airport Capacity Planning

SLB transactions accelerate fleet modernization. When United executes an SLB on 50 737 MAX aircraft in a single year, it is acquiring next-generation narrowbodies that carry more passengers per aircraft (up to 178 seats on the MAX 9) with better fuel economics. For airports, this can mean that an airline maintains or increases enplanements with fewer daily operations — affecting landing fee revenue calculations that are based on operations or weight, while potentially increasing passenger-driven non-aeronautical revenues (concessions, parking).

Aircraft Type and Airport Infrastructure

Airlines leasing new-technology aircraft (A321neo, 737 MAX 10) bring larger narrowbody aircraft to gates designed for earlier-generation equipment. The A321neo, with a length of 44.51 meters, requires more ramp space than the A320ceo it replaces. Airport use agreements define the facilities available to signatory airlines, and gate sizing, hydrant fueling capacity, and bridge compatibility are all affected by airline fleet mix decisions that are, in part, driven by lessor availability and lease economics.

Lease Return Conditions and Airline Financial Stress

Operating leases contain return condition provisions requiring the airline to return the aircraft in a specified maintenance state. Spirit Airlines disclosed that lease return costs "will increase as individual aircraft lease agreements approach their respective termination dates." For airports served by financially stressed carriers, the approaching end of a lease book can signal either fleet rationalization (fewer aircraft, fewer routes) or a decision to renegotiate or restructure — both of which affect enplanement forecasts.

The Lessor as Counterparty

When an airline fails — as Spirit Airlines did in 2024 and again in 2025 — the lessor repossesses the aircraft and remarkets it to another carrier. From the airport's perspective, the aircraft may leave the market it serves entirely. The lessor's decisions about where to place remarketed aircraft are driven by demand from airlines globally, not by airport air service development priorities. In a market where six lessors control the plurality of the world's leased fleet, the lessor's portfolio decisions have downstream effects on airport traffic patterns that airports do not control and may not anticipate.