In-flight meals. Given today’s norms for national air travel, it’s hard to remember when you actually got a meal (as opposed to bringing your own onboard in coach from someplace in the airport, or buying a “snack box”).
Of course international travel is different, and some of the overseas airlines still make a nice ceremony out of the thing. And if you go Business Class or First Class you do get a decent meal.
Even on the US national airlines, though, I’ve noticed that air travel is one of the most obvious places where Americans reveal their base attitudes about class. There are different check-in lines, security lines, and boarding protocols based on class (basically ticket price). It’s always amusing to see the shuttle flights out of dinky Eugene Oregon when they first call to board the prestige flyers, who get to walk aboard over a separate little rug. Then they call out the next boarders and those folks are supposed to walk on a different path which is right next to the little throw rug the 100K clients use. And dthen you get on a little airplane where everyone is seated just like everyone else, and actually the most desirable and comfortable seats are in the back exit row.