Indian airline SpiceJet has agreed to buy up to 205 new planes from Boeing – potentially worth $22bn (£18bn).
The deal includes a firm order for 100 new planes, 55 from a earlier contract and the right to buy a further 55 jets.
SpiceJet is India’s fourth largest airline, though its future looked in doubt in late 2014 after planes were grounded due to unpaid fuel bills.
India is set to be the world’s third biggest aviation market by 2020 making it vital for both Boeing and Airbus.
The number of people flying domestic routes rose by 21% in 2016. This growth in passenger numbers, along with lower fuel prices, has helped several of the country’s main carriers to make a profit.
Boeing said the first of the Max 737 planes would be delivered to SpiceJet in 2018.
“This is the largest deal for SpiceJet, it’s one of the largest in Indian aviation and is the largest for Boeing in India,” said SpiceJet’s chairman Ajay Singh.
“We are now in a very good position to expand our network and operations, which includes both domestic and international routes and destinations.”