Much like the difference in land use with or without cars is not simply roads and parkings, but also the horizontal development of cities rather than vertical, the land use involved by planes is not simply the airstrips. Among others, it is also all the land developed specifically for vacation in remote places. If you look at [1] for instance, this area would simply not be developed if planes were not a thing.

[1]: https://www.google.com/maps/@21.1715988,-86.8077681,1041m/da...