I appealed to an authority, but did not do an Appeal to Authority fallacy. I am saying IT'S RELEVANT TO THE TOPIC: he is an expert. I am distinguishing his likely knowledge, saying he's not just any pilot ... and piloting is the POINT here, not his beliefs on other things.

Have you never met someone who believes in ghosts but is an excellent mechanic, or whatever? The fact they believe in one thing is not relevant NECESSARILY to the other thing.

IF however we found that he believes in ghosts and thinks the car runs by ghost energy, then that would be relevant.