Several years ago I had an airport design program that used or mimicked the AFCAD UI, and had real-time updates to FS9 via FSUIPC.  I've been looking, and the closest thing I can find is ADE, which doesn't seem to be it at all.  I remember I got interested in it because of a banner on the AVSim downloads main page that had a GIF of an airport with parking spots being moved.

Anyone have any clues?