On the subject of Summer 2008, it is very early stages and many tour operators will not even contracted airlines to operate their programmes, and consequently airlines will not have applied for slots. XLA could very well change to FJE (if Flyjet continue operation) and other airlines may step in/change etc.
Having a little browse through Thomson's website indicates that not all of their flights/holidays have been released for Summer 2008 as not flights to AGP, ALC, IBZ, PMI etc are showing as yet, which is a whole aircrafts worth of flying, so unless a dramatic cutback in flights from NCL is planned, there is more to come!
Mytravels website still showing flights on FJE, basically all their flights for summer 08 are the same as this year, also indicating some changes are bound to occur.