A town of 2500 people counts as urban in the census[1]. There is nothing "urban" about a small town of 2500 people.

[1] https://www2.census.gov/geo/pdfs/reference/GARM/Ch12GARM.pdf

Your reference says that's an "Urban Place" and that "Urban Areas" are bigger. The post you responded to linked to something that said 220 million live in 486 "urbanized areas". Since there are many more than 486 towns above 2500 people, I think the 80% number refers to "Urban Places" and not "Urban Areas."

EDIT - it seems the number of what we'd normally call urban is around 70% with about 10% in "Urbanized Clusters" which seem to be "Urban Places" that we think of as suburbs??

And I would be one of them. I might live in an big apartment building in a city of over 10,000 but we do not have an airport. We do not have a costco. We have car dealers, but not the honda dealer I need for my recalled airbag (nearest is 400km away). And my particular urban area is not where my parents live. Urban or not, I still have to drive considerable distances for nearly everything.

Driving your own car to an airport is usually not a great idea even if you have one that can make the trip easily.

There's not much of an alternative if you live 100 miles from the airport. Even if you could find an Uber the cost would exceed the parking fee.