What is the woman afraid of when she takes her trips?

M: Are you looking forward to your trip to Canada, Susan?
W: I can’t wait to see Canada, Jason, but I’ m scared of the journey. My husband insists on flying, but I want to sail. Planes make me nervous.
M: There’ s nothing to be frightened of. How many planes do you think fly across the Atlantic every day?
W: I’ve no idea. Hundreds, I suppose.
M: And how often do you hear of a crash? Once or twice a year?
W: Yes, but aero-planes fly so high and fast that once is enough. Aero-plane crash is always terrible and seldom one can escape from death.
M: There are more people dying in road accidents per day than air deaths per year. Air transport is really much safer compared with road transport.
W: 1 still prefer to go by sea. Ships; may not travel fast but as least you can relax.
M: It’ s fine if you’ re a good sailor, but have you ever traveled far in a rough sea?
W: No. I’ ve only been in a boat once. I sailed down the River Thames on a sightseeing tour.