Flights were very different back then. I had a hospital room mate once that told a lot of stories about how in the 50s (maybe 40s? He was serving in Korea at some point, probably 40s now that I think about it) he and his friends would just sneak in amongst the boarding crowd on flights from NY all the way to Japan. They’d hang out in Japan, then do the same thing to get back to NY. The crew didn’t really check tickets of small kids. They’d literally just mix with the crowd and waltz in.

As for where they sat on flights, it was mostly in the some kind of luggage area. Apparently the flight staff had a routine where they all had a meeting in the front of the plane at the beginning of the flight, and that was when they’d sneak to the back.

It was one of those stories that was too crazy to be bullshit.