Airport Design for FS2004?

What application would I use to create a Airport from the ground up in FS2004? If there is a list of software needed, could someone list what they are and what you use each one for?
Thanks
Thanks
Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=16&t=37955
Before you build the airport you may first need to level the land (called 'flatten')and clear any unwanted objects like trees and buildings (called an 'exclude').
...or is flattening and excluding one function?.....
....Also i dont know how to add my buildings, exclude, and level the land...