IndiGo, India's largest domestic airline, has switched 125 of its existing Airbus A320neo jet orders to the longer range A321neo model, according to an Airbus source.
IndiGo now has 150 of Airbus SE's A321neo jets on order, the source said. The orders showed in the official October review on Airbus' website.
InterGlobe Aviation Ltd's IndiGo is one of Airbus' biggest global customers with 430 jets on order. It has almost triple the market share of nearest rival Jet Airways, which recently grounded some planes as it struggles to conserve cash and turn its business around.
IndiGo had previously said it plans to add to its fleet of Airbus A320neos and ATR 72 turboprops at a rate of around six planes a month.
It will add 30 percent capacity this financial year to maintain dominance of the world's fastest-growing aviation market, although its parent company has just recorded its first quarterly loss since listing.