Nordic low-cost airline Primera Air has ceased all operations and is expected to go into administration.
Stansted said travellers due to fly with the airline should not travel to the airport, from which Primera operated flights to Spain and the US.
Stansted told the company it would seize one aircraft, which was already on the ground and was not due to fly on Monday, because of unpaid bills.
Birmingham Airport referred customers to the Civil Aviation Authority advice, which urged those expecting return flights to the UK with the operator to make fresh arrangements home.
Primera, which has operated for 15 years, began offering flights for £99 across the Atlantic from Stansted to New York, Boston, Washington, and Toronto this year.
In a leaked email sent to news organisations, including Sky News, Primera’s director of operations Anders Ludvigson, said the airline would file for bankruptcy on 2 October and stranded crews would be found accommodation.
The airline was forced to cancel flights from Birmingham to America because of a delayed aircraft.
It later decided to end operations from Birmingham altogether, leaving many people out of pocket for their purchased tickets.
On its website, Primera said: “Airline Primera Air and IATA codes PF and 6F have been suspended as of today, October 2nd, 2018.”
“On this sad day we are saying goodbye to all of you.
“Kindly understand that the usual options for contacts (via email or phone) can not be offered any longer.”
Primera Air, which is Icelandic-owned but based in Copenhagen, began in 2003 and served more than 20 countries.
Mr Ludvigson blamed the airline’s collapse on the high cost of leasing planes after the delivery of new planes was delayed.
A London Stansted Airport spokesperson said: “We have learned this afternoon that Primera Air has ceased all flight operations and will go into administration at midnight tonight.
“Passengers due to travel with Primera Air are advised not to travel to the airport and instead contact the airline direct for the latest information regarding their flight.
“We understand this is a difficult time for customers whose travel plans have been disrupted and we are providing information and assistance to those who have already travelled to the airport for flights that had been due to depart today.”
The Foreign Office said its consulate in Malaga had already been contacted for advice by a Briton.