EasyJet has grounded its entire fleet of planes and said it cannot give a date for when they will restart.
The budget airline said it had made the move due to the “unprecedented travel restrictions” imposed by governments globally due to the virus pandemic.
It had already cancelled most flights but had been running rescue flights to repatriate Britons stranded abroad.
The move came as regional airline Loganair said airlines were unlikely to survive without a government bailout.
The pandemic has had a severe impact on airlines, Loganair boss Jonathan Hinkles told the BBC’s Tom Burridge.
He said that any airline saying it could survive without government help “would probably be lying”.
EasyJet said its cabin crew would be furloughed, with staff paid 80% of their wage from 1 April through the government’s job retention scheme.
The budget airline’s boss Johan Lundgren said he was “working tirelessly” to make sure the airline was “well positioned to overcome the challenges of coronavirus”.
“I am extremely proud of the way in which people across EasyJet have given their absolute best at such a challenging time,” he added.
EasyJet’s headquarters are at London Luton Airport and it has 331 planes. In normal times, it serves 159 airports and 1,051 routes.
Mr Lundgren said the airline had operated its last rescue flight on Sunday 29 March, but would continue to offer further rescue flights “as requested”.
The vast bulk of flights to and from the UK have been grounded due to travel restrictions imposed to control the spread of coronavirus, with many airlines expected to seek government help to survive.
Virgin Atlantic has already indicated that it will seek a bailout and airlines such as EasyJet are expected to follow suit.
The government has said it will only step in to help struggling airlines “as a last resort” on a case-by-case basis.
But industry group the International Air Transport Association (IATA) has warned of an “apocalypse” in the aviation sector as it urged governments around the world to help.
Loganair’s Mr Hinkles warned that the connectivity of remote Scottish islands and rural communities across the UK “cannot be maintained without air services”, arguing that government support for his airline was “essential”.
Loganair operates routes to the UK’s most remote airports such as Barra in the Outer Hebrides, where 19-seater planes land on the beach.
It is still running a higher proportion of its flights than other airlines because some travel to the most remote parts of the UK is still considered essential.
The airline is still ferrying people, mail and essential goods, such as pharmaceutical products, out to about 15 island airports.
Some of the most remote routes are subsidised by the Scottish government.