The airline, based at Leeds Bradford Airport, said that as a result of the Covid-19 pandemic, its board expects to report a group loss before foreign exchange revaluation and taxation from continuing operations for the financial year ended 31 March 2021 of between £375m - £385m.
This compares to a group profit of £262.2m before hedge ineffectiveness, foreign exchange revaluation and taxation from continuing operations were accounted for.
During the year to March this year, Jet2 said it took "swift and decisive action" to raise close to £1bn in liquidity from a diversified range of funding sources, to mitigate the impacts of the Covid-19 pandemic.
In addition, the business was forced to undertake many actions internally to reduce cash burn and preserve cash.
It said: "As a result, our liquidity position is strong with the Group's cash position as at 31 March 2021 comprising unaudited Total Cash of £1,379m and "Own Cash" (excluding advance customer deposits) of £1,062m (2020: £520m), an increase of 104% on the prior year end. This was after promptly returning over £1.3bn of customers' deposits for which we were commended by both the UK Civil Aviation Authority and Which?"
Jet2 said the continuing successful rollout of vaccines in the UK and the increasing momentum in Europe were both encouraging.
"Additionally, on 9 April, we welcomed confirmation from the UK Government's Global Travel Task Force that international travel remained on track to reopen in mid-May," it said.
"However, we were disappointed at the lack of clarity contained in the Task Force's report, in particular the as yet to be populated 'traffic light' framework for destinations, and full details and cost of the associated testing regime.
"This means the impact and duration of the proposed Covid-19 travel restrictions for Summer 21 remain difficult to determine and due to this continued uncertainty, in fairness to all our stakeholders and especially our Customers, we took the difficult decision to extend the suspension of our flights and holidays from 17 May up to and including 23 June, by which time we are expecting more clarity."