PARIS — Indian budget ******* IndiGo finalized an exceptionally large order for 250 single-aisle Airbus A320neo jets on Monday to keep up with rapid growth in the country’s air travel.

IndiGo, India’s largest domestic *******, had signed a preliminary order last year and firmed it up Monday, Airbus said in a statement. Airbus called it the biggest ever order by number of jets for the planmaker based in Toulouse, France.

At list prices, the jets would cost $26 billion, though customers usually negotiate discounts.

Several Asian low-cost carriers are building up fleets amid growing demand, and both Airbus and rival Boeing Co. have been wooing Indian ******* companies.

India is expected to become the third largest aviation market globally by 2020, with the number of ******* passengers tripling to some 450 million trips per year, as an expanding middle class trades up from slow train journeys to taking a plane.

IndiGo’s president, Aditya Ghosh, said the order would allow his company to further develop low-cost travel in India and abroad. The company has already taken delivery of around 100 Airbus aircraft that were part of an order for 180 aircraft worth $15.6 billion signed in 2011.

Despite the projected growth, airlines in India are generally unprofitable due to high fuel costs and stiff competition. Except for IndiGo, most other airlines, including state-owned Air India, have been incurring huge ****** and are in financial distress.

The A320neo is an upgraded, more fuel-efficient version of Airbus’ popular A320 jets, usually used on mid-range flights.