A flat cost line can hide a rising cost base
In 2025, reported unit costs at three US airlines came in flat or lower. Fuel got cheaper. Strip fuel out and unit costs rose at all three – 3.1%, 4.6%, 6.2%. Mostly labor contracts signed years earlier. The reported number moved on a fuel price they do not set. The ex-fuel number moved on a cost base they own. Only the reported one made the headline. Most P&Ls have a fuel line.
US airlines, FY2025: reported unit cost vs unit cost excluding fuel
Method: CASM = operating expense ÷ available seat miles
Sources: Southwest, American and JetBlue FY2025 Form 10-K filings.
Note: Each carrier defines its ex-fuel measure differently; all exclude fuel and special items.
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