Granted, yes, it was more like Japan is today in that sense but never the less, I maintain my point that flying wasn't something Joe or Susie did, it was the something jetsetters did --people who could afford the luxury of flying. They were not your farmboys and bricklayers who went flying taking their kids on a cheap leisure vacation to Disney, etc...

Still, you see these people had crisp pressed suits, not ratty and raggy well worn suits.

Indeed; I believe casual dress in general-purpose, public adult leisure contexts was initially associated strongly with the upper/upper-middle classes and was seen as a signal of higher status, even in cases where the dress item in question was an appropriation from the working class (e.g., jeans).

This is one thing I remember from the movie Endless Summer: the two surfers still wear a suit and tie to the airport.

I still wear a jacket while flying. To me, clothing is an outward sign of respect to those around you and is very effective when interacting with airport staff. A smile and a suit coat can get you amazingly far when your flight is delayed, cancelled, etc. You are treated differently at an airport when dressed appropriately.

which, in 21st century, is plain wrong. if I go hiking for 3 weeks in Nepal and have only outdoorsy clothing with me, I should be treated exactly same as everybody else. equality and whatnot.

I know it's how we all react on daily basis, everything is evaluated with some emotional context, but that doesn't make it a good behavior and something to be okay with.