In this photo taken on Feb. 7, 2016, A Iranian Mahan Air passenger plane takes off as a plane of Iran’s national air carrier, Iran Air, is parked at left, at Mehrabad airport in Tehran, Iran. Boeing Co. said Tuesday it signed an agreement with Iran Air “expressing the airline’s intent” to buy its aircraft, setting up the biggest business deal between the Islamic Republic and America since the 1979 U.S.