Flying? We were solid middle class in the 80s and my first plane flight wasn't until 2001 (and then only because I was away at college and my mother had died suddenly). My parents hadn't flown since the 70s (before my sister and I were born), and even then, that was a rare thing for them.
Our childhood vacations were single-day (so we didn't have to pay for a hotel) road trips to a nearby state to go to an amusement park, or multi-day trips (also within driving distance) where my dad had to go somewhere for work and the hotel was paid for by his employer. It was a huge huge deal for us when, in the late 90s, we drove down to Disney World (a 13-hour drive) for a several-day trip.
And we never traveled around Christmas; that was one of the most expensive times of the year to travel!
Not sure when or where you grew up, but most middle-class folks in the US in the 80s didn't have a lot of discretionary income, and flights were (inflation adjusted) quite a bit more expensive than they are today.
I suspect your family was not as middle class as you think it was. You're describing a very similar childhood to what I had in the late 80s, but we were lower class for sure
I'm not saying that middle class families flew all the time in the 80s, but they absolutely could afford to if they wanted to make it a priority
A cursory google search seems to bear this out. Cheap flights in north america started in 1978 with some air travel deregulation.