How do I get over being so scared to drive and fly?

I am petrified of driving on the highway with someone or by myself. I was in a car accident years ago, but I wasn't driving and I wasn't physically injured. Nothing except delays happened to me on airplanes. I used to love to travel and now I think I would only be comfortable on a train or ship , but living in Missouri, I would still have to drive or fly to the nearest bigger city. Any ideas on why I am so afraid and/or how to cure it??