The company traded under the names Forever Cruises, Lee’s Travel, Oz Flights, Unique Cruises and Sumoflights.com and websites flyclub.co.uk, forevercruises.co.uk, leestravel.com, ozflights.co.uk and sumoflights.com.
Lee’s Travel was licensed to carry almost 5,000 passengers.
The CAA said it was collating information from the company and would be updating its webpages shortly.
Last week Lee’s Travel was ordered to repay its debt to Iata over a billing and settlement plan (BSP) default by November 30 or face having its agency accreditation stripped.
The agency had earlier in the week been suspended from Iata’s BSP due to the debt.
An Abta spokesperson said: "The majority of Lee’s Travel business was the sale of scheduled airline tickets under its Iata licence. If customers are in possession of their ticket the airline should honour it and allow the customer travel as normal.
"If the customer has paid in full but not been issued with their ticket they should contact their airline who should issue a ticket directly to the customer - part payments should also be honoured by the airline.
"The company also sold package holidays involving flights. These are protected under the Atol and customers should go to Atol to start the refund process.
"The company also sold cruise only packages. Customers with this kind of booking should be able to continue with their booking and should contact the cruise operator directly."
When contacted by TTG on Thursday October 25 a staff member at Lee’s Travel said they were unaware of the closure.