Icelandic airline Wow Air has ceased operating with all flights cancelled.
The carrier previously said it was in the final stages of completing an agreement over raising new funds with a group of investors.
Wow Air said in a statement: "Wow Air has ceased operation. All Wow Air flights have been cancelled.
"Passengers are advised to check available flights with other airlines.
"Some airlines may offer flights at a reduced rate, so-called rescue fares, in light of the circumstances. Information on those airlines will be published, when it becomes available."
The carrier connected Europe and North America via Reykjavik, with UK flights serving London Gatwick, London Stansted and Edinburgh.
The airline, which was launched in 2012, had a fleet of 11 planes and employed around 1,000 people.
Denise Riordan was flying to Ireland to meet her six-month-old nephew for the first time at his Christening, but will now miss the family reunion after her flight was cancelled.
She was hoping to fly from BWI Airport in Baltimore to Dublin but has now been left stranded.
She said: “The airline sent stock texts and emails offering a refund or rebooking but they aren’t in a position to do anything for passengers.
“I am considering whether to pay a lot of money to go anyway - family is so important - but it’s $2000 return now, when I’d paid $623.
“You get what you pay for, or not, as the case may be.
“I’m feeling so disappointed but I’m not going to let myself get angry.”
The Civil Aviation Authority said travel firms with an Atol licence are responsible for making alternative arrangements to bring their customers home if they are currently overseas with a Wow Air booking.
The regulator said there are a number of options for passengers who booked flights via other methods, including requesting a refund through credit and debit card providers or making a claim with their travel insurance provider.
