Here's the problem; I'm building a jet fighter that appears to be perfectly mirrored BUT when in flight it rolls to one side, specifically the left. I try to counter this by mirroring that side of the aircraft. This time when I tested it the aircraft rolled to the right. Whenever I mirror the aircraft to try and fix this the side of which the aircraft rolls switches. If you guys need it I can post an early version of the aircraft for you guys to investigate.
All good guys! For some reason it just magically decided to work after some hours! :) Thanks for the help! The plane is now up on my profile!
Look at the drag and see if some parts create drag on one side of the plane and on the other side. If that has happened, try mirroring just the part that is creating the problem. I hope this helps.
Are you mirroring the entire plane? Sometimes, deleting just one wing and mirroring just the wing, works for me... I have no idea why.