Airline Jet2 is proposing to cut 102 pilot jobs, the Balpa union has said.
The Leeds-based carrier is not due to recommence flying until July 15, by which time it will have grounded its entire fleet for more than three months.
It is the latest airline to begin consulting on redundancies as the aviation industry struggles to cope with the collapse in demand caused by the coronavirus pandemic.
Other carriers that have announced job cuts include British Airways, easyJet and Ryanair.
Balpa general secretary Brian Strutton said: “This is yet more evidence, if it were needed, of the free-fall in aviation and the knee-jerk way airlines are responding, especially as lockdown is gradually being eased.
“Many of the pilots whose jobs are on the line in Jet2 have just recently moved there after having lost their jobs at Thomas Cook.
“These pilots have been through the mill already.”
He added: “Despite being one of our least union-friendly airlines, I hope Jet2 negotiates in good faith and works with us on how we can mitigate these proposed losses and see Jet2 thrive in the future.
“As difficult as our relationship with Jet2 undoubtedly is, the airline plays an extremely important role, especially at airports in the north, and we want it to succeed.
“Once again, I reiterate my call for the Government to step in, call for a job cuts moratorium and work on a strategic support package to help this industry get through this crisis.”