Any American citizen whom Israel considers to be a resident is required by Israel to hold a valid Palestinian passport to enter or leave the West Bank or Gaza via Israel, the Gaza International Airport, or the Rafah or Allenby Bridge border crossing.
American citizens in this category who arrive without a Palestinian passport will generally be granted permission to travel to the West Bank or Gaza to obtain one, but may only be allowed to depart via Israel on a Palestinian passport rather than on their U.S. passport."
(Say what?)