It's not common in the US because in the early 70 airlines got congress to prohibit cost sharing mass transit projects between muni's and airports. That's why it's always a spur line instead of a normal stop when it exists. Because the project has to be funded as a separate thing.

So if you wonder why for instance the light rail in Santa Clara county passes 100 feet from the airport. But the nearest stop is a mile and a half away, that's why.

I only know this because congress very recently repealed that law.