Thanks for the clarification.
Alas, I had already tried this, but I figured maybe I did it wrong. So I've tried again, but I get the same black screen when I click 'Fly'.
I'll describe the exact steps I did, in case I've done something wrong!!
Created folder C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight. (I.e. created the Flight sub folder.)
Copied \Program Files (x86)\ThirdWire\Strike Fighters 2\Flight\FlightData.cat to the Flight folder I just made in step 1.
Ran CatPack in C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight, to extract only FlightEngine.ini. This resulted in a folder called FlightData being created under Flight, containing the ini file. (I.e. it created C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight\FlightData\FlightEngine.ini.) It also resulted in a new file called FlightData.index.txt, directly in the Flight folder.
I moved FlightEngine.ini from C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight\FlightData to C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight, i.e. I moved it up one dir, so that it sits in the directory you told me it should.
I deleted the (now empty) C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight\FlightData folder.
At this point, I started the game WITHOUT making any edits. But when I click on 'Fly' for any mission, the game just hangs on a black screen. If I remove the FlightEngine.ini file, the game launches fine.
Can you tell me what I'm doing wrong? It seems that simply putting the flightengine.ini file into C:\Users\Darren\Saved Games\ThirdWire\StrikeFighters2 Europe\Flight is causing the game to hang, even though I haven't got as far as editing it yet!