I've noticed that they seem to have made some rather strange errors as to the classes of parking in FS2004. For example, Wichita Mid-Continent (KICT) has no spots that are able to accept the 747 and 777, differing quite a bit from FS2002 and reality. :) Is there anything that I can do to fix this?

You have to wait for AFCAD from Lee Swordy, it *Should" be out in october. AFCAD will allow you to add gates to your airports :)

You could cheat and make the radius of those aircraft smaller with AITM so they will fit into smaller gates.Matt