American Airlines (AA) and its regional partner American Eagle have been forced to cancel hundreds of flights amid a dispute with pilots that has seen growing numbers reporting sick.
Their parent company, which won a ruling from a US bankruptcy judge earlier this month that allowed AA to impose new pay and working rules on pilots, has cancelled 300 services this week alone.
AA also blames an increase in maintenance reports filed by air crews.
While flight cancellations represent only 1.25% of the group's 24,000 scheduled flights, owner AMR Corp said it did not wish to inconvenience passengers.
AA has said it would cut its schedule to the end of October by up to 2% and it has told Sky News that there are currently no UK flights affected by the disruption.
Its statement said: “We are constantly evaluating our schedule based on operational and staffing resources, as well as seasonal demand, making adjustments when necessary.
"The schedule adjustments we are implementing will ensure we provide our customers with reliable service while minimising any impact to their travel plans.”
AMR is trying to slash its annual labour costs by about \$1bn (£600m) as it reorganises under bankruptcy protection.
Eight of its nine unions agreed to back cost-cutting contracts, with only the pilots holding out against the plans.