New Delhi, Nov. 10 -- Engine maker Pratt & Whitney has assured IndiGo that it intends to replace faulty engines of 40-odd grounded planes of the country's largest airline by end-June 2026, said two persons with knowledge of the development.

This move potentially will boost IndiGo's profitability this year and next, depending on the pace of engines replacement, reducing the carrier's reliance on costly leased planes to offset the nearly-10% unused aircraft on its fleet.

The airline flies two of three passengers in India.

Forty planes with Pratt & Whitney engines are grounded while 60 are flying.

"There is an assurance for a staggered improvement in the aircraft on ground situation with a June timeline," said the first person, on the co...