I was old enough to actually see the Pan Am 747-100 at Heathrow many times. Pan Am and TWA did use a lot of 707’s but eventually got the 747 and 747SP on the routes. This was because it was the 1970’s and like today, airlines are waiting on the newer aircraft to be built. The date for this photo was August 1977, taken on my Kodak Box Brownie. I was 18 years old. I took the 727 bus up from Crawley. Had to get out at epsom as I was travel sick and then catch the next one. No M25 in those days up through Tadworth and Epsom. Just 12 photos per reel of film I had. If I was lucky my dad would give me money to buy another reel in the shop on top of the Queens building spectators. So a max of 24 photos per visit and then a long wait to see if they developed ok. Could be a few weeks as money to pay for that had to be earned in Sainsbury where I worked. I was on about £28 a week then full time. These days take as many as you like and then download them when you get home. No flight radar so you had to spot the aircraft and read the registration manually. Missed a lot of aircraft back then. Used to try and get the registration as the bus went past the hangers by hatton cross. Not easy, you had one chance in a few seconds. Only ever remember one bus driver slowed and stopped. He must have been a plane spotter himself.