Balpa General Secretary Brian Strutton said: “We know that aviation is in the midst of the Covid crisis and we had been expecting easyJet to make an announcement of temporary measures to help the airline through to recovery.
“But this seems an excessive over reaction and easyJet won’t find a supply of pilots waiting to come back when the recovery takes place over the next two years.”
Johan Lindgren, easyJet CEO, said: “These are very difficult proposals to put forward in what is an unprecedented and difficult time for the airline and the industry as a whole. We are focused on doing what is right for the company and its long term health and success so we can protect jobs going forward.
“Unfortunately 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.
“These proposals are no reflection on our people at Stansted, Southend and Newcastle, who have all worked tirelessly and have been fully committed to providing great service for our customers."
ITV News Business and Economics Editor Joel Hills said easyJet had told Balpa it plans to make one in three pilots redundant.
He added: "Future of smaller regional airports looking very bleak as airlines downsize."
In a statement, Newcastle Airport said it was “saddened” to hear about the possibly loss of jobs in the North East.
They said customers could still buy easyJet flights from the airport.
Newcastle Airport said: “There is no doubt that the Covid-19 crisis is having a significant effect on the economy and jobs, and that our sector is being particularly badly hit.”
They continued: “Although the airline is proposing to cease basing crew and aircraft at Newcastle, easyJet flights from the Airport remain on sale and the Airport will continue to be part of easyJet's route network.”
ITV News has approached easyJet for comment on when these planned closures could come into force.
The budget airline has been hit hard by the coronavirus pandemic, which has ground both domestic and international flights.
The firm announced plans to launch hundreds more international flight from the UK from July, as it also secured a major cash injection of £419 million from investors to bolster its finances.
Holidaymakers will be able to fly from 14 airports across the UK to a number of countries including France, Spain and Italy.
From the start of next month, it will run around 500 flights each day across Europe, including over 900 flights a week to and from the UK.
On June 15, it restarted a “small number” of flights for the first time since its aircraft were grounded in March.
EasyJet said it plans to fly around half of its 1,022 routes in July, before increasing to around 75% in August.
The announcement follows from the announcement that air bridges will be available from next week to allow Britons to take holidays in some other countries without quarantining for 14 days.