Trade union Unite will enter talks tomorrow with Thomas Cook after the company announced the start of a 90-day consultation for 420 staff.
The travel giant is to cut its fleet of aircraft from 35 to 31 as part of a series of cost-cutting measures.
Unite regional officer Helen Osgood said: “Unite will enter these talks with the company in Manchester with the goal of saving as many jobs as possible.
“At present, details of the threatened job losses are sketchy – we are not even sure which airports that Thomas Cook flies from will be worst hit.
“This is shocking news to a loyal and hard-working staff at the holiday company. Unite represents about 400 engineers and 1,000 cabin crew out of the 2,700-strong workforce – and their future at this time is our prime concern."
She added: “It is very disappointing that this announcement has come at a time when the company’s new chief executive officer, Harriet Green has just been allotted 6.2 million share options, which is currently, we believe, worth more than £1 million.”
Responding to Unite's comment, a Thomas Cook spokeswoman said: "Thomas Cook strongly believes in pay for performance. The share awards for the new management team are subject to stretching conditions and will only be valuable if the business performance is transformed."