Plus the wellbeing of others is not something that's always on the mind of someone contemplating suicide. Jump off a building and you might land on someone, step in front of a train and you're probably going to fuck the driver up for life, in fact however you do it the chances are that for the person that finds your body (possibly a family member) it isn't going to be a pleasant experience, plus all the psychological trauma that entails.
I guess for a man who loved flying, that joyriding towards death, seeing how close you can get to the South Pole before the plane runs out of fuel might have an appeal...and you might even console yourself over the deaths of your passengers if you've convinved yourself that you gave them a painless, possibly even peaceful, death via hypoxia. Or he might just have put all thought of them out of his mind, acting as if, possibly even believing that, he was on his own.
Pure conjecture of course.