I think you are (ideally) supposed to pick up a biplane user manual from the library in Venice, but I don't know this actually changes the game. I myself forgot to do this on my current play-through, but I have a slight recollection that there's an alternate route (via land?) where you can bypass the plane section? However, my memory is so hazy that I can't be sure. I think I only played the game once in the 90s, as I could never get over back then how graphically inferior it was to Fate of Atlantis. I was spoiled by playing that one first.
I will try to do that on this play through. However, I'm currently struggling to get through Castle Brunwald -- the guards refuse to believe I'm a genuine servant.
Incidentally, this year marks the 30th anniversary of that game.