Stolen/defected aircraft.
There was a Ju88 late model nightfighter which defected by prior arrangement and was met by a waiting escort of Spitfires and taken to, I think, RAF Dyce in Scotland. This is described in detail by Eric Brown in his fascinating book “Wings of the Luftwaffe”. Brown also describes the arrival of a Fw 190 which appeared over, I think, RAF Chivenor (I’ve lent my copy of Brown’s book to German friend so I can’t check), did a victory roll and landed straight off the roll to be greeted by a quick-thinking NCO with a Verey pistol pointed into the cockpit. The pilot had, indeed, mistaken the Bristol Channel for the English Channel!