It's hard for me to tell. Whenever I ride on a machine at 30,000 ft above the ground at 300 MPH, I take a Xanax (or three, funny story, but I have been "carried" off of flights by friends and family) to help me forget the previously mentioned facts. If I ever remembered that there's software on those machines, I'd probably take my pills with alcohol. Either way, when I get to my destination I always sleep for about 10 hours.
Off topic, I heard a great programmer joke; a bunch of programmers are hanging out and talking about code and such. One of them says, "show of hands, would you ever get on a plane if you knew your company wrote the software that controls the airplane?" A single hand goes up out of the group. "You believe that your company writes software that well?!" questions the programmer that brought up the topic. The man with his hand up replies, "No. I'm just not that worried about troubles from our software mid-flight; if my company wrote the software, the plane would never even take off in the first place."