They laid off thousands of workers during the global health crisis.
And now, airlines in the U.S. are scrambling to hire them all back again.
Travel demand is rebounding and carriers suddenly facing a shortage of all kinds of staff, not just pilots.
That's sparked a pay battle for workers.
American Airlines subsidiary Piedmont is trying to lure pilots in with an $180,000 bonus offer.
United is offering a $5,000 signing bonus for some ground staff.
Spirit, the low-cost carrier, has raised some wages by 30%, and is helping flights attendants pay back tuition fees.
Big names like United and Delta are also poaching workers from smaller operators, where wages are lower.
But the soaring wage costs are coming just as fuel prices are jumping as well, and with airport charges on the rise too.
That has left airline profits feeling the squeeze.
Critics say the firms only have themselves to blame.
U.S. airlines made savage job cuts last year, despite getting $54 billion in federal aid to help cover payroll costs.
The cuts have left them short of workers as demand snaps back.
Staff shortages are one factor behind the recent rash of flight cancellations.
They could also stop carriers from serving less profitable routes altogether.
United has already decided to drop eight routes in the Midwest and South as a result of pilot shortages.