The operator confirmed last week that they were cancelling large numbers of mainly charter flights from the airport next summer.
Customers have been asked to switch their flights to different airports to ensure their package holidays can still go ahead.
A source from the airline industry said that six destinations currently served by TUI would not return for the 2019 season. TUI have been approached to confirm the information.
They are: Antalya, Turkey; Burgas, Bulgaria; Dubrovnik, Croatia; Ibiza; Paphos, Cyprus and Rhodes, Greece.
Leeds Bradford Airport confirmed that the six airports are still served by other operators based at LBA, with 25 flights available in total to the above destinations if booked with airlines such as Jet2 and Ryanair.
The landing slots vacated by TUI will be offered to other airlines already operating out of Leeds Bradford.
TUI's scheduled flights to Corfu and Majorca will continue, as will their chartered cruise flights.
TUI, formerly Thomsonfly, had one aircraft based at Leeds Bradford and offered mainly European package charter flights.
One customer from Middleton in south Leeds said she had been contacted by TUI to inform her that her May 2019 holiday to Majorca could only go ahead if she agreed to change her flight times, while others were asked to fly from a different airport or have the booking refunded.
Another tourist said he had lost one day of his 10-day family holiday with TUI because the flights had been moved to Doncaster Sheffield Airport and had been offered only £50 in compensation.
A statement from TUI said:
"We’ve been able to re-look at our summer 2019 programme and we’ve made a few changes to our flight schedule. We’ll be moving an aircraft which was due to be based at Leeds to another airport within our regional network as we continue to support growth at some of our key focus airports for the year ahead. This has resulted in a number of flights being cancelled from Leeds Bradford Airport. We are directly contacting any affected customers with alternative travel options and offering a gesture of goodwill."