American Airlines Group Inc. and United Airlines Holdings Inc. said some Boeing Co. aircraft won’t arrive until 2023 or 2024 amid lingering uncertainty over when the planemaker will be allowed to resume deliveries of its 787 Dreamliner.

The issue has already prompted American to reduce, delay or suspend some planned international routes, a setback for the carrier as global travel is beginning to recover from a pandemic slump. The delays are also contributing to higher unit costs by limiting flying capacity and idling pilots trained to operate the aircraft, American said on a conference call to discuss earnings Thursday.

Boeing has been grappling with structural glitches that have turned its popular wide-body jet into a cash drain and prompted the U.S. Federal Aviation Administration to step up inspections of each jet before delivery. The manufacturer, which suspended Dreamliner deliveries in May 2021 to address the defects, can’t resume until the FAA completes necessary reviews.

American now expects to get seven 787-8 Dreamliners toward the end of this year, too late to be used during the busy—and lucrative—summer travel season. Three more won’t show up until 2023, joining a trio that was previously delayed until that year. Four 787-9 variants of the aircraft American thought it would get in 2023 have now moved to 2024. 

Boeing has committed to covering financial “damages” from the delays, the airline said.

At United, two 787s and seven of Boeing’s 737 Max aircraft slipped into 2023 due to “supply-chain and manufacturing challenges,” finance chief Gerry Laderman said on a call with analysts. The airline expects to receive six other 787s and 46 Max jets this year. 

It’s also working with Boeing, the FAA and Raytheon Technologies Corp.’s Pratt & Whitney division to finish modifications to 52 Boeing 777-200s that were grounded after an engine broke apart in early 2021 departing Denver. That fleet—which represents about 10% of United’s capacity—will return to service over the next nine months, executives said Thursday.