Mumbai, Mar 13 (PTI): Budget carriers IndiGo and GoAir cancelled as many as 65 flights on Tuesday after the country's aviation regulator Directorate General of Civil Aviation (DGCA) grounded 11 of their A320Neo planes with faulty Pratt & Whitney engines, causing severe inconvenience to hundreds of flyers.

While the Gurugram-based IndiGo cancelled 47 of its 1,000-odd flights per day, the Wadia Group-promoted GoAir said it had cancelled 18 flights.

GoAir has cancelled 18 flights originating from over eight cities, the airline said in a statement to news agency PTI.

GoAir operates 230 flights per day.

IndiGo announced on its website the cancellations of some 47 flights across its domestic network for Tuesday. The flights that have been cancelled are from Delhi, Mumbai, Chennai, Kolkata, Hyderabad, Bangalore, Patna, Srinagar, Bhubaneswar, Amritsar and Guwahati, among others.

Later in a statement to the media, IndiGo said the affected passengers have been given the option to either choose another flight at no additional cost or cancel their booking and get a full refund without any cancellation charges.

"IndiGo has cancelled certain flights due to the grounding of our aircraft further to the DGCA directions which has been issued in the interest of safety," the airline said. "While we understand that this may cause inconvenience to some of our passengers, given that we have multiple flights to the same destination, we are proactively re-accommodating all our affected passengers on other flights," it added.

The DGCA cracked the whip after an IndiGo flight bound for Lucknow returned to Ahmedabad within 40 minutes of its getting airborne due to a mid-air engine failure on Monday.

Citing safety of aircraft operations, the Director of the DGCA, in the March 12 order, said that A320Neos fitted with PW1100 engines beyond ESN 450 have been grounded with immediate effect. Three other IndiGo A320Neo planes have been on the ground since February following similar engine problems.

On Monday, hundreds of passengers were stranded across the country as dozens of flights were cancelled by IndiGo and GoAir due to the grounding of the 11 A320 Neo planes of the two carriers. IndiGo carries about 40 per cent of domestic flyers, while GoAir has a market share of around 10 per cent.