N751PA was, of course, ex Pan American who managed the occasional visit to Luton in the 70's operating subs for the resident airlines. Only 707 I know of was N766PA on 25/7/71 on a Britannia flight. 727 N323PA on 11/8/73 was probably operating for Court Line, then this one (N356PA) on 24/7/78 was probably doing a Britannia trooping flight, arriving as "Clipper 159F" (which must have raised a few eyebrows when it called Luton Approach). Apologies for the picture quality:-
Same aircraft was back on 7/9/78, BY918 from Hanover, then N329PA on 12/9/78. It was a summer of horrendous ATC delays (the French - surprise, surprise) and the holidays airlines were bringing in a variety of aircraft to bail things out - Aeroamerica 720, Trans European 707, Balair DC-8, BA Trident, Geminair 707, S.A.T.A Caravelle, Lufthansa 727 were amongst the aircraft used during the peak summer.