Tata Group-owned Air India has placed an order for 840 planes with Airbus and Boeing, including the option to acquire 370 aircraft, with a senior airline official on Thursday saying the order is a "landmark moment" in the Indian aviation history. The announcement by Air India's Chief Commercial and Transformation Officer Nipun Aggarwal comes a day after the airline said it has placed a firm order for 470 aircraft -- 250 from Airbus and 220 from Boeing.