Passengers stranded across Europe have told of their frustration after the UK regional airline Flybmi collapsed, cancelling all its flights.
The airline, which flew to 25 cities, said Brexit uncertainty and rises in fuel and carbon costs led to it filing for administration on Saturday.
One Briton stuck in Belgium said the airline would not refund her fare and she could not afford an alternative.
Flybmi's move puts 376 jobs at risk and comes as other airlines face problems.
On Sunday, Loganair stepped in to take over three Flybmi routes from Aberdeen to Bristol, Oslo and Esbjerg. However, these will not start until 4 March.
The two carriers are owned by the same holding company, Airline Investments.
Flybmi has told affected travellers to contact their insurance and credit card companies. Flybmi, based near East Midlands Airport, operated 17 aircraft.
Durham University student Mary Ward says she discovered her flight could be affected when her she received a BBC News alert.
She then received a text from the airline that said: "URGENT: Important message for Flybmi customers. All flights are cancelled. Please go to www.flybmi.com for further details. Thank you."
Ms Ward had been set to fly from Brussels to Newcastle but is unsure how she will return to the UK.
"I paid £130 for my flight which it doesn't seem I'm going to get back - I don't know how I am going to get back to Durham," she said.
"I can't afford any of the flights or the Eurostar."
Richard Edwards, from West Sussex, said he and his family experienced problems with a scheduled flight to Munich when travelling to Austria for a skiing holiday.
"We had gone through security at Bristol Airport when there was an announcement saying our flight had been cancelled," he said.
"They laid on taxis to Heathrow and booked us on a Lufthansa flight to Munich.
"I don't know how we will get back yet. I'm not confident Flybmi will be able to sort it."
Great start to our holiday; en route with @Charlot53066691 and the family by taxi to Heathrow as our @flybmi from Bristol to Munich (which had previously been changed from Southampton) was cancelled with no explanation after we had gone through security! 😬😬😬— Richard Edwards (@RA_Edwards9) February 16, 2019
Rory Boland, travel editor for consumer body Which?, said some customers had claimed tickets were being sold in the hours before the airline filed for administration, "knowing full well those tickets would never be honoured".
"Passengers will rightly be outraged if this is proved to be the case," he added.
Flybmi issued the following advice to those with flights booked:
- People who booked directly with Flybmi should contact their card issuer to seek a refund
- Passengers who booked via a travel agent or one of Flybmi's partner airlines should contact them to ask about their options
- Those with travel insurance should see if they are eligible to claim for cancelled flights
The Civil Aviation Authority also published advice for travellers.
A Flybmi spokesman said: "It is with a heavy heart that we have made this unavoidable announcement.
"The airline has faced several difficulties, including recent spikes in fuel and carbon costs, the latter arising from the EU's recent decision to exclude UK airlines from full participation in the Emissions Trading Scheme.
"Current trading and future prospects have also been seriously affected by the uncertainty created by the Brexit process, which has led to our inability to secure valuable flying contracts in Europe."
One of Flybmi's routes, which connected Stansted and City of Derry airports, was subsidised by the government to boost trade and travel between Northern Ireland and the rest of the UK.
Several people use the flights for work and Derry Strabane Council said it was in emergency talks with the Department of Transport to seek a replacement airline for the route.
Very disappointing news that @flybmi have gone into receivership - Council would like to reassure the public that its officers & reps from @CoDerryAirport are in emergency talks tonight with UK Dept for Transport to urgently seek a replacement airline pic.twitter.com/zIohtlo4HQ— Derry Strabane Cncl (@dcsdcouncil) February 16, 2019
Several airlines have folded or reported financial trouble during the past two years, with analysts blaming fierce competition, rising costs and falling passenger numbers.
Britain's Monarch collapsed in October 2017, while Germany's Germania filed for insolvency earlier this month. Air Berlin and Alitalia, and a string of smaller operators hit trouble.
Ryanair boss Michael O'Leary warned this month that the airline industry would see more bankruptcies.
Flybe, another UK airline, has said that if a rescue takeover by Virgin Atlantic is not approved by shareholders, the airline's holding company will close.
Flybe has been forced to reassure customers on social media that it is "not associated with Flybmi" after concerns were raised by some passengers.
The managing director of Loganair, Jonathan Hinkles, who on Sunday said the airline will take over three former Flybmi routes from Aberdeen next month, said that "there is no doubt that trading in tough" for many airlines.
"It's always really sad to see an airline go out of business, and our thoughts are with all those affected - particularly staff members," he said.
We are very sorry to hear about the situation with the competing British regional airline Flybmi and our thoughts are with their employees during these difficult times. Flybe has nothing to do with Flybmi and our flights continue to operate as normal.— Flybe ✈ (@flybe) February 16, 2019
Analyst Peter Morris, of the aviation consultancy Ascend, said the start of the year is always the worst time for airlines as they struggle to get through the winter and wait for a summer pick-up in bookings.
But he was in no doubt that Brexit uncertainty and questions around freedom of movement beyond 29 March would have hurt Flybmi. There are issues around the regulatory status of UK airlines after Britain leaves the EU.
Other smaller airlines are "definitely vulnerable", he told the BBC. "But even the big boys might have some problem with the aviation environment."
Travel expert Simon Calder told BBC News: "Small airlines which do not have the weight of their bigger rivals are particularly vulnerable," he said. "There are simply too many seats and not enough people."
Flybmi's operations were formerly run as BMI Regional, a division of the airline BMI. The company was formed in 2012 when British Airways owner IAG took over BMI and sold the subsidiary.
The airline last year ran 29,000 flights carrying 522,000 passengers.
A spokesman for the Department for Transport described the situation as "very disappointing" and said the government was focused on supporting affected passengers.
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