TUI @ LTN
Its a fair point that TUI use easyJet for a large part of their flight programme out of Luton, but to me it still doesn't stack up. The airline and tour operator have their HQ and aircraft maintenance facilities in the town and to have almost a skeleton presence at that location makes little sense.
The airline has shown their commitment to remaining in the Luton area for their HQ, with them recently announcing they would be centralising a lot of their sister European airline ground operations in Luton.
easyJet also has a huge presence at Gatwick, Manchester and Bristol, and these TUI bases continue to go from strength to strength, so there is more to this than meets the eye.