Re breaking one's fast on the plane.
Even though the the shkia is seen for a long time - does one break one's fast according to the time of tzeis hacochavim of the place over which one is flying.
Answer:
Yes. The time of nightfall depends on the place over which one is flying, and not on the seen shkiya on the plane (Yerushalayim Be-Mo'adehah, p. 232, in the name of Rav Shlomo Zalman Auerbach; see Iggros Moshe, Orach Chaim Vol. 3, no. 96).
