Easyjet
I cant say that I am surprised that Gatwick is going, Ive used it a few times and its always been busy but no doubt the slots can be used for more profitable routes. I did give it a bit longer though but always knew it would go.
Im quite surprised Easyjet still have a base at Newcastle they dont appear overly keen on seeing the base grow and develop. As for a 4th based aircraft I cant see it happening in fact I would not be surprised, although I would hope not, if the base were to close in the next couple of years.