Terrafugia's FAQ has some useful info including this comment:
The Transition also reduces the cost of ownership of an airplane by burning automotive gasoline, parking in your garage at home instead of renting a hangar, and nearly eliminating ground transportation costs.Good points! So OK, I have a private pilot's license and a two-car garage that's within a 25 minute drive of at least three airports. I would love to have one. But aside from gasoline, hangar charges, and various insurance issues, a key factor in "cost of ownership" is the price - $279,000. Maybe not this year.