???? ???? ?? ????? ??? ???? ?????? ????? ?????? ????? ?????? ????? ????? ???? ?????? ????? ?? ?? ????? ??? ??? ???????.?????? ?? ??? ???? ?????? ??????? ?????????? ?????? ??? ? ?????? ????? ?? ?? ???? ??????? ????? ???????. ?? ?????? ?????? ???? ???? ???? ? ??????? ?? ?????? ???? ???.Jet aircraft are propelled by jet engines, which might be utilize