Yes you can. There a a couple of freeware programs available to do that. RW12 or SBuilder are both available here or at other sim download sites. RW12 is probably the easier to learn/use. Visit the Scenery and Panel Design forum here for more info.

You might also consider adding their ac as ai traffic. That can be done using Afcad to add necessary parking to the airport and TTools to program the ai flightplans. Both programs are freeware, available here, and reletively easy to learn/use. You can visit the Adding Aircraft Traffic... forum here for more info.

Dave