I remember flying BA as a teenager with my dad from HK to London on a 741 in the middle of the 70s.

A few observations:

• Everyone dressed up to fly in all cabins
• We had two stops (one in Mumbai and the second stop was somewhere in the middle east)
• We had four full meals in economy. Food was much better back then.
• Writing paper, envelopes, post cards, playing cards were widely available throughout of the plane
• It was useless to have non-smoking and smoking sections in the plane. Although the smoking section was in the back of the plane, there were a lot of smokers (who sat in the front of the plane) came to the back of the plane to smoke. The back of the 741 was standing room only with smokers. The whole plane looked like a closed off smoking room at the airport.
• The headsets were the tube kind that looks like the doctor's stethoscope‎s
• Those projection IFE was of poor quality that was impossible to see with window shade up during daytime flight.

Most of my flying as a kid were on CX, BA, Pan Am and Lakers due to my father being an expat and I was in boarding school in England. Heathrow, Gatwick, old Hong Kong and Miami were the airports I remember the most. None of them stood out. In fact Heathrow T3 arrival area has not changed much since the 70s.

• Passengers seemed to be more sociable and a lot of readings on the plane back then, I guess there was no individual IFE, mobile devices to keep passengers entertained.