easyJet has begun consultations on plans to close bases at Stansted, Southend and Newcastle.
The low-cost carrier confirmed earlier this year it would reduce staff numbers by a third as it battles back from the coronavirus shutdown.
The Unite union said nearly 1,300 crew members faced losing their jobs in the UK.
At the same time, pilots’ union Balpa said it had been told by the carrier that 727 of its UK-based pilots were also at risk of redundancy.
That is equivalent to one in three of its pilots, Balpa said.
easyJet chief executive, Johan Lundgren, said: “The lower demand environment means we need fewer aircraft and have less opportunity for work for our people.
“We are committed to working constructively with our employee representatives across the network with the aim of minimising job losses as far as possible.”
easyJet currently has 11 bases in the UK, with 163 aircraft, serving 546 routes.
The carrier has seven aircraft based at Stansted, with 335 crew.
At Southend, there are 183 crew and four aircraft, while there are three aircraft based in Newcastle, with 157 crew.
easyJet has started to fly passengers again, but does not expect 2019 levels of demand to be reached again until 2023.
Also today, easyJet said it had been notified by the Haji-Ioannou family that it no longer holds a 30 per cent stake in the issued share capital of the company.
The change comes as a result of a non-pre-emptive placing announced by the carrier on June 24th.
Accordingly, the relationship agreement between the company, easyGroup and Stelios dated November 14th, 2014 (which was put in place to comply with the controlling shareholder regime set out in the listing rules) has terminated in accordance with its terms.