British airline Flybe said Saturday it had ceased trading and all flights had been cancelled.
"We are sad to announce that Flybe has been placed into administration," the airline tweeted.
"Flybe has now ceased trading. All Flybe flights from & to the UK are cancelled & will not be rescheduled," it said.
The UK Civil Aviation Authority advised passengers booked with Flybe not to go to the airport.
"It is always sad to see an airline enter administration and we know that Flybe's decision to stop trading will be distressing for all of its employees and customers," CAA consumer director Paul Smith said in a statement.
"We urge passengers planning to fly with this airline not to go to the airport as all Flybe flights are cancelled."
Flybe had only returned to the skies in April after it crashed into bankruptcy as the coronavirus crisis erupted and destroyed much of the travel market.
It operated up to 530 flights per week on routes from Belfast, Birmingham and Heathrow to cities across the UK, and internationally to Amsterdam and Geneva.
Before it went bust, it was a leader in the UK domestic flights sector.
Its assets were purchased by Thyme Opco, which is linked to US hedge fund Cyrus Capital.