The union representing 1,500 Thomsonfly staff has warned of strike action in protest at compulsory job losses.
The TUI UK carrier has been involved in talks on redundancies resulting from a current restructuring, but the union alleges the company is already preparing for the proposed merger with First Choice.
Thomsonfly and First Choice Airways currently duplicate operations at Gatwick, Manchester, Stansted, Bristol, Cardiff, Luton, Glasgow, Newcastle, Birmingham and East Midlands.
The T&G, now part of the new union Unite, said talks with Thomsonfly at conciliation service Acas have so far failed.
T&G industrial organiser Kevin Hall said: “We have already seen closures at Leeds Bradford and have been advised of Thomsonfly’s intention to close the Stansted and Bristol crew bases.
“We understand First Choice has announced the closure of its Cardiff and Luton bases from November 1.”
The union wants a guarantee of no compulsory redundancies and, without one, will ballot on a strike. A consultative ballot of cabin crew has already found that 98% support a walkout.
Hall warned: “Thomsonfly should be under no illusion. Our members’ jobs and their customers’ holidays are at stake.”
Unite revealed this week it has signed a recognition deal on behalf of cabin crew at Thomas Cook Airlines.