SABENA
The first trans Atlantic service from Ringway was surely SABENA with 707''s out of BRU onwards to Idelwald.
BOAC Cunard followed with a 707 service predating Tristars. It was the Speedbird 538 if I recall.
Don't forget the Canadians with CP Air and Air Canada followed later by Air TransAt and Royal
As for regular charters my favorites were American Flyers, ONA, TIA and Capitol.
Ah the Good Old Days!
Sir George Cayley
The air is a navigable ocean that laps at everyones door