The CAA has confirmed the firm’s licence was revoked on September 3.
Omega was licensed to sell 4,069 Atol protected holidays this year.
Milton Keynes based Omega traded under Omega Travel, Omega Flight Store, Sagitta Travel Agency, Newtrip, Jade Travel, Far East Travel Centre and Chinese Travel Shop.
It operated omegatravel.net, omegatravel.ltd.uk and budgettravel.co.uk.
It was incorporated under the Omega banner in 1996, but the company dates back in various guises to the 1960s.
Any passengers who booked an Atol protected holiday through Omega should contact the operator for a resolution.
A CAA spokesperson said: "We can confirm we suspended Omega Travel’s Atol licence on September 3, 2018.
“This means that while the Atol is suspended, the company cannot sell any Atol protected holidays or flights.
“Consumers who purchased an ATOL protected trip before the suspension can be assured that their trip is fully protected and are advised to contact Omega Travel to confirm arrangements."
The Sun further reports Omega’s participation in the BSP has been suspended by Iata.