Not sure why it needs a joystick. My original CD I have on an old computer plays fine with a keyboard and mouse.

From the store page:

IMPORTANT NOTICE: The Windows version of STAR WARS®: TIE Fighter (1998) requires a controller or joystick. STAR WARS®: TIE Fighter (1994) can be played with a mouse and keyboard.

It's because the 98 version has a different engine.

The later versions uses the X-wing vs Tie Fighter engine. For me, this is great, cause the joystick support is much better than Dosbox.

Yes this is my point. I have the 98 version on CD as well and I use a keyboard with it and mouse hence my OP.

i guess you have the "collector`s cd-rom" from 1995, not the edition from 1998...

[url=http://en.wikipedia.org/wiki/Star_Wars:_TIE_Fighter#Release]http://en.wikipedia.org/wiki/Star_Wars:_TIE_Fighter#Release[/url]