Airlines have more workers than they've had in 20 years, but they still might not have enough to handle what's projected to be a sizzling summer travel season.

Driving the news: United Airlines, which has already hired more than 7,000 workers since January, said Wednesday that it plans to add 8,000 more this year.

• The company has received more than 12,000 applications for more than 4,000 flight attendant roles, spokesperson David Gonzalez said in an email.

The big picture: The air transportation industry had an estimated 534,400 employees in March — up 9.5% from a year earlier and the most since April 2003, according to the Bureau of Labor Statistics.

• Those new workers are desperately needed.
• Delta Air Lines CEO Ed Bastian said in April that the company is fielding "record" advance summer travel bookings — and international trips are particularly hot.

Between the lines: An ongoing pilot shortage is "one of the hangovers from the pandemic," Going.com travel expert Katy Nastro tells Axios in an email.

• "Even with aggressive hiring efforts ... there is still a deficit due to the fact that it does certainly take time to become commercial pilot ready."

Zoom in: Airlines are grappling with surging wages amid labor shortages — and higher wages mean lower profits.

• Major airlines have signed deals for pilot compensation hikes of 30%, compared with pre-pandemic salaries, while wage inflation for other airline workers is up by 10% to 20%, according to Third Bridge analyst Christopher Raite.
• "All airlines, but particularly the mainline carriers, are structurally less profitable than they were pre-pandemic due to rising labor costs — particularly for pilots," Raite wrote in a recent research note.
• One way that airlines have responded to shortages is by reducing flights by about 10% compared with 2019, Nastro pointed out.

Reality check: Despite concerns about labor shortages, Bastian said Delta is "pretty much through the hiring."

• And Southwest Airlines CEO Robert Jordan said last week that his company "will be moderating our overall hiring plans" after previously pledging to hire more than 7,000 net new workers this year.

The bottom line: The summer travel season will put airlines to the test.