The largest low-fare airline was Southwest Airlines, which had 46,128 employees combined with its subsidiary AirTran Airways. JetBlue Airlines was the second largest low-fare employer, with 12,691 employees.
The announcement came as the trade group for airlines, Airlines for America (A4A), held a briefing on Wednesday to tout the performance of the industry.
A4A President Nicholas Calio said the airline industry was doing well in the face of rising gas prices.
"From a consumer perspective, it's a great time to travel by air," Calio said in a statement. "We are in the safest period in aviation history; our members are delivering record on-time performance, airfares have not kept pace with inflation and customers today have greater options to choose products and services they value."
"Airlines continue to aggressively manage against steep cost increase, including fuel prices, which are expected to hit a record high in 2012 and continue to outpace increasing revenues," A4A economist John Heimlich added.
The full BTS report can be read here.