Being from a mostly military and cargo background, I was shocked to see how terrified many people are about flying. After flying some of the public around on corporate gigs, it was a revelation to find out that many folks are scared to death to board an aircraft, but they do it anyway.
Please try to understand that it is a terror of the unknown, and yes it is dangerous. They just haven't had as much exposure to it as two cars (loaded with who knows what) passing each other on a two lane road at a 140 MPH closing speed.

Try to understand their fears and deal with them as gently as possible. And yes they can be very funny afterward. The fear is very real for them.

As others have pointed out, you never know, perhaps the designer of your aircraft is on board.