They were all off-duty, luckily for passengers, but more than 250 Frontier pilots picketed Frontier’s HQ in Denver today.

Why?

The pilots saved Frontier from the brink of bankruptcy in 2011, by giving up $55 million in wages.

Thing is, Frontier promised to pay it back once they got profitable again.

Frontier is apparently now profitable, but hasn’t budged in talks to start giving that money back to pilots.

This is from a press release from the Air Line Pilots Association (ALPA), the union that represents the pilots:

“Despite our pilots’ enormous sacrifice and the indications showing that Frontier Airlines is now extremely profitable and rewarding its investors, Frontier pilots are still the lowest-paid Airbus pilots in the country,” said Capt. Tracy Smith, chairman of ALPA’s Frontier pilot group. “The loan that Frontier pilots gave to our company is past due—we want industry-appropriate pay and benefits like our fellow pilots at other airlines.”

This photo was posted in a Tweet from ALPA.

Frontier recently filed to have an IPO of stock, but it looks like they may need to start paying its pilots better first.

1st time in company history Frontier Pilots Picket HQ. #PilotContractNow, #f9Picket pic.twitter.com/Uik2xpfqtD

— Frontier MEC (@F9ALPA) April 19, 2017