There are various ways that you can get all the different airlines. There are some payware programs (MyTraffic and Ultimate Traffic), and ProjectAI, which is free, but not quite as complex, and it's more involved to install (though by no means difficult, just time consuming). I use Project AI
myself. You can take a look at it at www.projectai.com.
Ultimate Traffic is at www.flight1.com,
and I'm not sure of the address for MyTraffic.
As for the trucks and buses, I don't know of any program that puts those into all the airports in FS
- they usually come as part of an airport scenery package. The good ones are payware (obviously), but there might be good freeware ones also. Unfortunately, I don't know much about scenery, since I don't use any add-on sceneries in my FS