From what I've read, particularly the accounts of pilots like Franz von Werra, a Swiss German pilot who successfully escaped back to Germany. Generally what would happen is that if you survived any of the many chances for death from being shot at in the air, dying from the crash, along with some reports of overly excited Home Guard members shooting at parachutists (I remember one story of a British Ace who was wounded from fire by a Home guard unit who thought he was German.) Generally once you reach the ground, you would get picked up by the Police or the Army, jailed in a cell or a barracks until properly interned in a POW camp (or kept in said cell or barracks for a while) but generally speaking, pilots were treated generally well.

I also read about the hilarious account of the capture of Armin Faber, a pilot who mixed up the Bristol channel with the English channel and landed his plane. He was split from his squadron, disorientated, and thought that he was landing in southern France when he was actually landing on the RAF Pembry station airfield (Even doing a victory maneuver with his wings) Because the station was for pilot training, the pilot who arrested him did so with a flare gun.