ABTA member Kanoo Travel has closed down.
The association said the company, which mostly dealt with business travel bookings, but also took sold leisure and scheduled air tickets, ceased trading on 30 June.
The company was based in Sheffield and had been in business for 15 years.
ABTA said: “If you were a corporate client of Kanoo Travel Ltd these sales were not protected with ABTA and you will need to contact the airline directly to check if your booking is still available.
“If you booked a package holiday through Kanoo Travel Ltd and the holiday is provided by another tour operator, you will need to contact the tour operator named on your paperwork or ATOL certificate for a flight inclusive package.
“Your tour operator should be able to confirm that they have your booking. Your tour operator will be responsible for your booking going forward.
“If you booked a flight-only with Kanoo Travel Ltd and were issued with a ticket or e-ticket, you will need to contact the airline that you are due to be travel with to ensure your booking will go ahead.”