If you look at a few of the very large airports like Ohare, Sea-Tac, Hearthrow, ect, with your dynamic scenery settings turned up, you should see a few ground vehicles around the airport

That was probably Lago's FSSE (Flight Simulator Scenery Enhancer) scenery. It's a payware program that allows you to place all kinds of scenery objects into the FS2002 virtual world. I think i've seen these shots also.

For more details or screenshots about this program, the best person around here to talk to is Fozzer. He will tell you everything there is to know about it.

???
I read a review of this software in Computer Pilot mag while in the US which was not too flattering.

There is a LOT of setting up to be done by the user, it only works on AI aircraft and not your own one, it has to be set up for each gate at each airport where you want to see action and ATC can't tell the difference between regular gates and ones that you've set up, so it will send AI planes to regular ones as often as 'special' ones unless you alter the priority using AFCAD.

The blurb tends to suggest everything happens automatically, but it doesn't.