The crisis has the industry scrambling for solutions.

At least one lawmaker is said to be considering legislation that could raise the federally-mandated retirement age for airline pilots from 65 to 67 or higher to extend aviators' time in the skies.

A regional airline proposed reducing flight-hour requirements before joining a U.S. carrier, and airlines are rethinking training programs to lower the barrier to entry. Earlier this year, Delta Air Lines joined other big carriers in dropping a four-year degree from its pilot hiring requirements.

Several U.S. airlines, including Frontier, are recruiting some pilots from Australia. American Airlines is selling bus tickets for some short routes.

But some airline executives warn the shortage could take years to solve.

"The pilot shortage for the industry is real, and most airlines are simply not going to be able to realize their capacity plans because there simply aren't enough pilots, at least not for the next five-plus years," United Airlines CEO Scott Kirby said on a quarterly earnings call in April.

Kirby estimated the regional airlines United works with currently have about 150 airplanes grounded because of the pilot shortage.

Roots of the crisis

The Covid pandemic halted pilot hiring as training and licensing slowed. Airlines handed out early retirement packages to thousands of pilots and other employees aimed to cut labor bills when travel demand cratered during the depths of crisis.