My first trip to Houston in 1971, three months after arriving in Calgary.
A Western Airlines 732 (or possibly a 720) - Calgary, Great Falls, Billings, Denver and then a Trans Texas (known as Tinkertoy Airlines or Tree Top Airlines) DC-9-10 - Denver, San Antonio, Houston. A long day.
Years later, leaving Houston on a Continental DC-10, there was a company DC-10 at the adjacent gate, going to Los Angeles, Honolulu, Fiji, Auckland, Sydney, Melbourne. I'm glad I was just going to Denver.