Kohanim on a Plane Saying Birchas Kohanim
Birkas Kohanim is a Torah obligation found in Sefer BaMidbar (6:22) , “Koh s’vorchu es Bnei Yisrael – thus shall you bless the children of Israel.” Indeed, the Gemorah in Sotah (38b) implies that if a Kohan does not do so, he is in violation of three Torah commandments. Yet, one of the main differences between a typical Shacharis service of an Ashkenazic shul and a Sefardic shul outside of Eretz Yisroel – is whether they say Birchas Kohanim. In Eretz Yisroel, both Ashkenazim and Sefardim recite it daily.
Outside of Eretz Yisroel, most Sefardic shuls do have the kohanim present recite the three-fold bracha. Ashkenazic shuls do not. They do so only on Mussaf of a Yom Tov (except for on Simchas Torah most do so at the Shacharis Shmoneh Esreh instead of at Mussaf). This discrepancy is discussed in the Rama in OC 128:44.
But what about on a plane flight to Eretz Yisroel?
When this author’s friend, Reb Shimon Brescher z”l asked this to Maran Rav Chaim zatzal, he ruled that on a plane flight, both to and from Eretz Yisroel, a resident of Eretz Yisroel must do birchas kohanim and someone who lives in Chutz la’aretz may recite it. Technically, someone even a Kohain who resides outside of Eretz Yisroel is permitted to recite the birchas Kohanim, it is just that the minhag in “places” is not to do so, and he should not do so because of “lo sisgodedu” do not change from the minhag of these places. However, an airplane is not considered an official “place.” Indeed, the Mishna Brurah (468:18) rules that in a wilderness, outside of the Techum, one may do as he wishes in this regard.
Maran Rav Chaim zatzal explained that there would be no problem of lo sisgodedu on a plane flight.
Throughout the years, of course, many leading Rabbanim have tried to re-implement in Chutz La-Aretz, but did not succeed. Among those who have tried to redo it are the Vilna Gaon, the first Lubavitcher Rebbe, Rav Chaim Volozhin and the Netziv.
See Shamanu Kain Ra’inu p. 220