That's a cool-lookin' plane. However, I can understand that the wings don't quite blend in with the "stealth" look you seem to be going for.
Should you decide that magic wings floating in midair (I can't see the body, can you?) is not what you're going for, my guess is it's an improperly installed addon, or a broken texture. If it happens with multiple objects, are there any similarities between them? Developer, installed date, etc. Maybe they both were obtained from the local cheese shop?
Also, what system are you running? Windows 95/98/NT/ME/XP/Vista/7/8/10? Has a reinstall helped?
Hope I can be of some help