Delta Air Lines (DAL)
Premium-skewed US network carrier: FY2025 adjusted TRASM of 19.56¢ against CASM-Ex of 13.86¢, the Monroe refinery as fuel hedge, non-GAAP FCF of $4.64B.
Educational analysis for professional use. This profile is not investment advice or a recommendation to buy or sell any security, and it is not personalised.
Snapshot
Premium Unit Economics
Delta's ex-fuel unit spread is about 5.7¢ a seat mile, but only when revenue and cost are measured on the same basis. Airlines are compared per available seat mile (ASM), one seat flown one mile. Delta flew 298,045 million of them in FY2025, 3% more than a year earlier. Passenger revenue per ASM (PRASM) was 17.37¢ and GAAP cost per ASM (CASM) 19.31¢.
CASM-Ex, Delta's own ex-fuel cost measure, strips out fuel (3.29¢), the cost of refinery products sold to third parties (1.70¢) and profit sharing, the staff bonus pool paid out of profit (0.45¢). It still includes depreciation and aircraft rent. Because the refinery's cost comes out, its sales must come out of total revenue per ASM (TRASM) too. Adjusted TRASM of 19.56¢ less CASM-Ex of 13.86¢ gives the 5.7¢. Take CASM-Ex from reported TRASM of 21.26¢ instead and you keep the refinery's revenue without its cost, which overstates the spread at 7.4¢. United and American exclude different items, so the RASM and CASM guide reads each carrier's reconciliation before lining the spreads up.
Monroe Refinery as Fuel Hedge
Delta hedges fuel by owning a refinery, Monroe Energy at Trainer, Pennsylvania, and carries no broad derivatives book on passenger fuel. Monroe does not supply Delta with below-market fuel. The FY2025 adjusted fuel price of $2.30/gallon, an all-in figure including taxes, delivery and the refinery's result, sat above the 2025 average Gulf Coast exchange price of about $2.11/gallon (EIA, the US Energy Information Administration). Monroe's contribution is refinery profit that offsets part of the fuel bill, and it swings with refining margins. The fuel and hedging guide sets it beside Southwest's 2025 exit from financial hedging and the rolling hedge books of European groups such as Air France-KLM.
Our models use a mid-cycle US Gulf Coast jet fuel price of $2.85/gallon: WTI at $70/bbl plus a jet crack, the refining margin for turning crude into jet fuel. Market prices wander far from that. Gulf Coast jet was $4.354/gallon on 22 September 2026 (EIA), so a margin screened on last quarter's fuel line misstates what an airline earns through the cycle. The mid-cycle price is a teaching input for this page's worked examples; it forecasts nothing.
Balance Sheet and FCF
Delta guides leverage down from 2.4× to about 2× in FY2026 and to 1× over the long term. Leverage here is adjusted debt, which counts operating lease liabilities, divided by EBITDAR, which is EBITDA before aircraft rent. The EBITDAR guide explains the pairing: once leases sit in debt, the fixed part of rent must be added back to earnings, or it is counted twice.
Free cash flow does the deleveraging. Delta's FY2025 figure was $4,643 million on its own non-GAAP definition, which differs from operating cash flow less capex. In a normal earnings year that is what moves the ratio towards 2× without new equity.
What to Watch in the Financials
The spread holds only if costs stop outrunning revenue. CASM-Ex rose 2.4% in FY2025, and premium fares can hide labour and aircraft-ownership inflation for a while. If costs keep climbing as TRASM settles back, the 5.7¢ narrows towards United's 5.2¢.
Load factor, the share of seats sold, was 84% on the 3% capacity increase. IATA put North America at 82.9% for FY2025, and mature networks usually run from the low-80s to the high-80s. Growth that pulled Delta below the low-80s would hit passenger unit revenue before costs could adjust.
Valuation Framework
Airlines are screened on EV/EBITDAR using normalised earnings, because trailing P/E and other trailing multiples whipsaw with fuel. The typical band runs roughly 4–7× EBITDAR, with a 5.5× model anchor. Delta's normalisation trap is the refinery: GAAP TRASM includes refinery sales, so airline EBITDAR should start from adjusted TRASM, with Monroe's contribution treated separately and the same way every year.
Key Risks
Reported FY2025 fuel cost is no guide to a bad year. Adjusted fuel of $2.30/gallon sits below the mid-cycle price and far below 2026 market prices. Dearer fuel raises GAAP CASM but leaves CASM-Ex untouched, so headline and ex-fuel measures drift apart.
Premium revenue is cyclical. Corporate and front-cabin demand drove Delta's TRASM, and a slowdown in front-cabin fares shows up in PRASM before capacity plans change. Monroe adds a second commodity exposure, refining margins, that network peers without a refinery do not carry. Its sales and costs run through both revenue and cost, so when jet prices and refining margins part company, reported fuel economics can move while the core airline margin stays put.
Peer Context
United grew ASMs 6.1% at TRASM of 17.88¢, with net leverage of 2.2×. American carries $30.7 billion of net debt, the most of the three network carriers, with FCF near zero. In the Airlines Sector Primer comp set, Delta is the premium-network case and the only US major that owns a refinery.
EBITDAR builds from a thin unit margin on seat miles, the leases are capitalised into net debt, and the value moves on what a small load-factor drop costs.
The Excel model is the primer's airline build live across 11 sheets: EBITDAR from seat miles and unit margin, leases capitalised into adjusted net debt, a through-cycle EV/EBITDAR valuation for a network carrier and a low-cost carrier, a load-factor downturn, a lease-adjusted leverage screen and a sensitivity grid. Change the unit revenue, fuel or leases and the value moves.