"The funny thing was it was written for me. But it was not written well enough yet -- the plane stuff, not the character... I loved that he was an alcoholic and I loved his journey a lot. But the plane stuff was silly, from my perspective. Flying upside down -- it's a bit much. I just wanted those bits to get redone. I asked the writer, 'Did you not ask a professional or someone who knew something?' And he said, 'I didn't want any interference -- I just wanted the screenplay done. To hell with that stuff!'"
By the way, Travolta is a professional pilot, so I suppose he would have a bit more insight into the technicals.
But it is the movies, right - suspension of disbelief and all that.
Although I doubt Denzel Washington is losing any sleep over that, since he received an Academy Award Best Actor nomination for his portrayal of the character, and several other honors.