> I could just show up 60 to 30min before take off
In the early 90's I showed up at a check in counter for a domestic flight from SYD 1 minute before scheduled departure time and the lady there apologized and told me that I missed the flight because it had left a little early.
I think I remember a Trump Shuttle print ad from, presumably, 1989 or 1990, saying that you'd better not show up for a flight at 6:00:01 if the scheduled departure is at 6:00:00.
This principle still works for Swiss and Japanese trains, but it might be a little harder for people to relate to for air travel nowadays!
In the early 90's I showed up at a check in counter for a domestic flight from SYD 1 minute before scheduled departure time and the lady there apologized and told me that I missed the flight because it had left a little early.