If you've been searching for US flights lately and found fewer choices at higher prices, it's not your imagination. The three biggest US carriers — United, American and Southwest — have all signalled they'll trim flight schedules because jet fuel has become dramatically more expensive. Speaking at Morgan Stanley's annual investor conference in September 2026, executives from all three airlines confirmed they're adjusting capacity in response to fuel costs, which per IATA tracking had climbed more than 100% year-on-year by mid-September. The spike is tied to the Iran war, which began in February 2026.
United's CFO Michael Leskinen was the most specific, warning that some December flights already on the books won't operate, and that if fuel stays expensive, cuts will extend into the first quarter of 2027 and beyond. He didn't name the affected routes. It echoes a memo United CEO Scott Kirby sent in March, when the airline cancelled roughly 3 percentage points of off-peak flying — think red-eyes and Tuesday, Wednesday and Saturday departures — across the second and third quarters.
Southwest CFO Tom Doxey said the airline has already reined in planned growth and may cut schedules further if "fuel is higher for longer," while American CEO Robert Isom struck a similar tone. Delta has already acted: it paused some domestic routes over summer 2026, including JFK to Memphis and Houston Intercontinental. American also trimmed summer service from Los Angeles to Cleveland, Columbus, Pittsburgh and Washington Dulles, plus Charlotte flights to Ontario and Sacramento, explicitly blaming fuel prices.
For travellers, the pain comes twice. With carriers flying fewer planes, remaining seats cost more — CNBC reported US airfares were up over 26% in June 2026 compared with June 2025. Several airlines have also leaned on fuel costs to justify higher checked bag fees this year.
What does this mean if you're planning a trip? Off-peak days and times are the first to disappear, so the classic advice about flying Tuesdays or taking red-eyes may become moot — those flights simply might not exist. Booking earlier matters more than it used to, since popular routes are likelier to sell through at peak prices. And if a fare looks reasonable right now, it may be worth locking in rather than waiting for a dip that capacity cuts could prevent from ever arriving. Flexibility helps too: travellers on routes like those Delta and American already cut may need to connect through hubs rather than fly direct.