IndiGo, India’s largest domestic airline by market share, has agreed to buy 250 A320neo aircraft from Airbus Group NV in the largest such order in terms of aircraft numbers for the European plane maker.

IndiGo and its co-founders, Rakesh Gangwal and Rahul Bhatia, group managing director of InterGlobe, have signed a memorandum of understanding for the deal, Airbus said in a statement on Wednesday. While Airbus did not provide financial details, the plane's list price, excluding discounts, values the deal at almost $26 billion dollars.

IndiGo has previously placed orders for 280 Airbus aircraft comprising 100 A320ceo and 180 A320neo, according to the statement. The additional 250 planes will help the airline expand its operations in India and overseas, Aditya Ghosh, president of the no-frills airline, said in the statement.

Bloomberg reported in April that IndiGo is seeking an initial public offering of shares to raise $400 million that would help the airline expand faster in a region where demand for air travel is rising.

The A320 family is the world’s best-selling single-aisle aircraft with almost 11,000 orders to date, Airbus said in the statement.