I recall a vacation with my parents as a teenager that went PHL-YYZ-open - train travel-YVR-PDX-open -SEA-LAX-PHL, which was the first time I had encountered two books of coupons stapled together. BTW, Dad trusted 16 yo budding avgeek me to research the flights and train schedules and go to the travel agent with Mom to make the reservations. Afterwards said it was the best-planned vacation he ever had.

A year later I planned a solo (had been soloing since I was 14) PHL-PIT-DSM-ORD-PHL to visit the families of my siblings. Because of a death in the family, PHL-PIT became MDT-PIT, and the ticket agent at MDT pasted a sticker on my first coupon to change the flight information.

Ah, the fun days of paper tickets, when you had to be sure you had your tickets with you as you left the house!