Can you use FS2002 a/c in FS2004?

Generally, yes. If the panel was made for FS2002 you will have to modify panel.cfg so that it uses the FS2004 GPS gauge.

To also add--if the aircraft was made in FSDS 1.x, some animations won't work--mostly prop animations. But if your aircraft has reflective textures, then it had to have been made with either GMAX or FSDS 2--and other than panel mods as already mentioned, it will work with no problems...-John Edit: Also, I added a shot to my cloud screenshots in the screenshots forum that you'll be interested in...

Thanks John and other replier.I went and bought it (FS2004) today, and wallah! It is the real thing! almost...The clouds are brilliant and it is dark!!There are improvements to be made (like sun reflections during overcast? Unless it wasn't fully overcast.But having that makes you think it is extremely smoggy anyway.I will get to use the map soon.talk soon, thanks

Well I suppose Meljet are all ok to use with FS2004 then, right?

"(...) wallah (...)" Would that by any chance be "voil