What add on allows you to see inside airports? I seen a few videos where people were inside a airport?
It’s up to each individual addon developer to create an airport building interior.
Some do, some don’t.
You’ll need to check the reviews of places that interest you to see if they have created interiors or not.
Quite a few of the Asobo handcrafted airports have some interior elements.
To actually see inside the ones that have the interiors modeled, just use the drone. Not long after I got the sim, I went to a local store that sells used books and movies, along with games and gaming hardware. I found an Xbox controller for about $20. It had a couple of sticky buttons, but a small screwdriver and some rubbing alcohol took care of them.