You are correct, that although the basic principles of physics are simple as to why planes can be made to fly, the practice of keeping an aircraft in good working order is very complicated.

I used to fly around Alaska in helicopters when I was doing fieldwork as a graduate student, and the pilots used to say about a helicopter that it is "8,000 pieces flying in formation." That probably does not make you feel better about flying, though.

The answer to why airplanes don't crash more often is MAINTENANCE. The crews work very hard to make sure the aircraft is always in good working order. Occasionally they fail, and it is a tragedy.

So, how can you feel better about flying? You need to look at the statistics. Look up how many flights there are per day; per week; per month; per year. Then look up how many crashes there are per day, week, month, year. You might also want to know how many "near misses" there are- but that might be very difficult to find out, as you'd have to get all the flight records from all the flight towers around the world. And maybe you don't want to know the near misses! They don't count - after all, none got hurt. So, just look at the actual crashes.

This would make an interesting study - you would need to decide on your research questions: Are you going to break this down by airline? By airport? By city? By country? By size of aircraft? By aircraft manufacturer? What is your population, and what is your sample? Then you could compute the likelihood of having an actual crash by category, and over all.

Bottom line: proper maintenance keeps airplanes from crashing, but there is never absolute zero probability of having a crash. Perhaps if you do a statistical study, you could make yourself feel better by minimizing the likelihood of experiencing a crash. After you've done all that, be sure you follow the safety directions when you do fly.

And if you still don't want to fly, well, that is your choice. Some people actually manage to live successful lives without ever flying, but you will have to allow extra time for travel if you are going to drive or go by boat.

And, I hate to say it, in today's world, aircraft maintenance is not the main reason to fear flying. It is terrorism. But - if you let fear keep you down, then you won't go anywhere. Nothing is sure; everything has risks, so you just have to choose "wisely."

I spent a wonderful summer in Bulgaria, Macedonia, and Turkey, while war was (and still is) happening in Iraq, bombs were going off in the London subways, and other bad stuff was happening in Israel-Palestine and Sri Lanka. But I had a great time, I met tons of travelers from all over the world, and I was perfectly safe everywhere I went.

You are absolutely correct that a machine with more moving parts is a more technically challenging machine. The reason why aircraft are as safe as they are is because they are maintained. Automobiles, for example, are not quite as complicated as aircraft but are still pretty complicated. Yet, if a car engine fails, it's not a disaster; the car will come to a stop, and it can be repaired. If an airplane engine fails, it will have to make an emergency landing, and if the airframe fails, it will crash, probably killing its occupants. As a result, airplane mechanics are much more particular about the quality and the condition of the parts they use for their aircraft than automobile mechanics and automobile drivers are about their vehicles. This kind of "maintenance whether need or not" attitude is what makes aircraft so expensive relative to cars.

Now, driving, of course, is more dangerous than flying. This is because of human error and the density of cars: careless (or drunk) drivers crashing into other cars. By being a select few (again, airplanes are expensive), pilots are more responsible than drivers, and there is room enough in the sky for planes anyway, and there isn't room for all the cars on the roads.

You are right, that will all the different components, the working parts, the chances that one of them could go wrong is high. Two things make air travel safe. The first is that very strict rules are followed in who can fly a plane and how planes are taken care off. We might take a car to a repair shop one a year, but planes are taken to repair hangers nearly every few days.

Also, there is a lot of redundancy built in. What this means is that people make sure that the whole plane will not fail just because some small part fails. The best example of this is that the 4-engined Jumbo can actually fly on just one engine. So do fly. Its actually much safer than driving.