Is It A Plane?

I could hear an airliner- and thought I'd spotted it- and then the white cruciform object veered away from its forward course in a tight curve- and I realised it was a gull.

I wonder why gulls venture so far inland. Ailz suggests it's for the rubbish dumps but if it's food they're after why would they fly so high? I like to think its for the pure existential pleasure of being up there, riding the thermals.