I flew in 1972 and I don’t think D.B. Cooper really had that much of an effect on how airports worked, other than to make it impossible to open the rear door on a 727 in flight. There wasn’t much in the way of security. I was a little kid, and unknown to my mother, I had brought a toy cap gun with me that looked like a real revolver if you didn’t look at it too closely. We had already checked in our luggage, so the guy at the counter made my mother put it in her purse to keep it hidden, and that was that. I think it’s a fair bet that it wouldn’t have been handled that way today.
There were a lot more hijackings in the early 70s, many of them after Cooper. I think it was around 1974 or 1975 that they really started to clamp down as far as security goes.
We flew on one of them new-fangled 747 planes, so everyone was excited about that. I got to go up into the cockpit once the plane was in flight, and they gave me a toy 747 made out of balsa wood. This type of thing, only shaped like a 747:
Like @Napier, I also got a wing pin. The toy plane and wing pin were given to me by a stewardess. They weren’t called Flight Attendants back then.
We were still in the golden age of flying back then (if just barely), so everyone was super nice, and they fed you decent food. My mother took care of IDs and passports and that sort of thing so I have no idea what that was like.
While security does factor into some of it, I think most of what the OP is complaining about has more to do with just trying to shove everyone through the system as fast as possible these days. The golden age of flight is definitely long gone. Not only is the airport a madhouse, but the planes themselves pack you in like steerage. They carefully schedule flights to avoid meal times, so that all they have to serve you is a bag of trail mix, and not even that on shorter flights. They want you to eat in the super-expensive airport facilities where you pay $20 for a McDonald’s hamburger. Everything is about maximizing profits, not providing good service.
Smoking was also a thing. There were curtains that were supposed to separate the smoking from non-smoking sections of the plane, but smoke still drifted into the non-smoking section. Not everything was better back then.
Another thing from back then that you don’t see today were the Hare Krishnas and other religious/political groups that made a beeline for you as soon as you entered the airport. I think the Krishnas used to hand out flowers. Lots of other folks would try to force pamphlets on you. They made fun of this in the movie Airplane, but I don’t think folks in the younger generations who watch the movie these days really get the joke.
I avoid flying as much as possible these days. It has become absolutely miserable.