Airbus and IndiGo finalized a deal, the Indian budget airline ordering 250 A320neo aircrafts, according to the BBC. The agreement was finalized on Aug.15, the 69th Independence Day of India, according to Airbus.

This is Airbus' largest quantity of planes ever sold at one time, and its second-largest order by value, according to the BBC. It also makes IndiGo the biggest airline customer of Airbus' A320 aircrafts, according to Reuters.

The deal, which was originally announced in October, is worth $26.55 billion at list prices, according to Reuters.

The president of IndiGo, Aditya Ghosh, said this in a statement:

"This new order further reaffirms IndiGo's commitment to the long-term development of affordable air transportation in India and overseas. The additional fuel-efficient A320neo aircraft will enable us to continue to bring our low fares and courteous, hassle free service to more customers and markets and will create more job opportunities and growth. The IndiGo team is even more energized and excited than ever before to herald this new phase of our growth for many years to come."

The delivery of these planes will begin in 2018, and will likely take until 2026, according to Reuters.

This deal with IndiGo helps solidify the lead Airbus has in its competition with Boeing, according to the BBC.