Icelandic airline Wow Air has suddenly stopped all flights, leaving thousands of passengers stranded around the world.

A travel alert published on Wow Air’s website said that the airline is ceasing all operations and cancelling future flights as efforts to raise more money failed. The airline, which flew a total of 3.5 million passengers last year, advised passengers to book new flights on other airlines, and said some may be eligible for compensation.

“The reality is that we have run out of time and have unfortunately not been able to secure the funding of the company,” said Wow CEO and founder Skuli Mogensen in a letter to the company’s 1,000 employees, Reuters reported. Wow Air operated short and long-haul routes to various cities in Europe, and to Washington, Boston and Detroit in the U.S.