The A-6 in WOV also has this problem. I cut and pasted an answer from one forum member, but unfortunatly I don't know who it was. I havn't tried his solution yet, so I'm not sure if it works.
This is what he said;
"Much of the 3w and 3p aircraft use the game's canopyglass.tga hidden in Object cat file.
The easiest way to replace this is to find another tga, say totally clear, and rename it canopyglass.tga and place it into the aircraft's folder, sometimes the skin folder, or the cockpit folder. Try all these locations if needed. You can find a clear tga in Cellinsky's sky mod here at the CombatAce, where Cellinsky offers totally clear tga's to replace the sim's horizon cloud tga's.
There are other deeper methods."
Hope that helped.