Fear of flying

Fear of flying
I've read somewhere that around 20 million people in North America are afraid of flying and this of course can interfere with their career. It is very interesting because I've never thought about it and I have a friend who is afraid of flying and she had a very hard time because she had to go on a business trip to Sydney, Australia. You just can't take the bus or the train..... So what do you do? Quit your job?