A long time ago an airline psychologist/flight crew trainer told me this theory and it worked to help me get over the fear:
The fear is strongest when you are afraid of leaving behind (dying) someone you love very much and whom you believe will be lost without you! So, for example if you have underage children who are dependent upon you--that adds to the fear. Once those children are older and out on their own your fear starts to leave in correlation to how much traveling you want to do. In other words it gets easier when you are not afraid of abandoning your loved ones!