New Delhi, Aug. 22 -- At the end of work trips, Nathan Miller goes home to a makeshift bedroom in his parents' house in Virginia. The 29-year-old flight attendant is part of a PSA Airlines crew based in Philadelphia, but he can't afford to live there.

Miller says he makes about $24,000 a year staffing multiple flights a day as a full-time attendant for the American Airlines subsidiary. To get to work, he commutes by plane between Virginia Beach and Philadelphia International Airport, a distance of about 215 miles.

"I've considered finding a whole new job. It's not something that I want to do," Miller, who joined PSA two years ago, said. "But it's not sustainable."

His situation isn't unique. Frustrations among flight attendants at both...