The U.S. government has granted Airbus a license to sell 17 passenger aircraft to Iran, a landmark deal estimated to be worth about $25 billion. The deal by the European manufacturer has been pending since January and was made possible by last year's nuclear agreement between the major world powers and Iran. Sanctions that had barred companies such as Airbus from trading with Iran were lifted after Tehran agreed to curb its nuclear development program, but the European firm still needed U.S. approval of the deal. Iran Air agreed to buy several different types of planes, including the single-aisle A320 and the double-decker A380. Iran's fleet of aging passenger jets badly needs upgrading, as a result of years of deferred maintenance during the time when international sanctions were in effect against Tehran, curtailing the country's ability to acquire spare parts for the aircraft. American manufacturer Boeing Co. reached a tentative agreement with Iran at the beginning of this year that also could be worth $25 billion. If that deal also is approved by the U.S. government, it would be the biggest commercial transaction between Iran and an American corporation since 1979, when Iran's monarchy was toppled by its Islamic revolution, protesters stormed the U.S. Embassy, and the Tehran government held 52 Americans hostage for more than 14 months.