After days of cancellations that stranded thousands, IndiGo is gearing back up towards full service, with 1,650 flights likely on Sunday compared with significantly reduced operations late last week, chief executive Pieter Elbers said.

Elbers, in an internal video message from IndiGo’s operational control centre, said on-time performance should reach 75 per cent on Sunday as the airline recovers from disruptions linked to new flight duty rules and other operational pressures that stretched crew availability.

“Step by step, we are getting back,” the CEO said, adding that cancellations were being executed at an earlier stage to ensure passengers do not reach airports unnecessarily. IndiGo currently serves 137 of its 138 domestic and international destinations.

The aviation ministry, which has pressed the airline to complete refunds for cancelled flights by Sunday evening, said IndiGo has so far processed Rs 610 crore in refunds and delivered 3,000 pieces of baggage that were separated from passengers.

No additional fees may be charged for rescheduling travel impacted by the cancellations, it added.

“The ministry has taken rapid and decisive steps to ensure passengers do not face continued inconvenience,” the government said, noting that other domestic carriers are operating smoothly with full capacity.

IndiGo generally runs around 2,300 flights a day. A senior airline official said operations should be fully stabilised by December 10, stressing that pilot numbers were adequate but buffers were tighter than at other airlines.

“There is no hiring freeze. Our pilot numbers are fine; we just did not have the luxury of a bigger buffer,” the official said.

The second phase of the revised FDTL norms, permitting fewer night landings, came into effect from November 1. Since then, operational disruptions escalated this week, prompting the Directorate General of Civil Aviation to serve show-cause notices to Elbers and Accountable Manager Isidro Porqueras.

A root-cause analysis will be carried out to determine the precise triggers behind the crisis, the official said, calling the situation a “learning experience”.

IndiGo expects to maintain readiness for the fog season with sufficient pilots and aircraft in place.

The government said all corrective measures will remain in force until operations are “entirely stable”, and constant communication with passengers has been mandated to minimise inconvenience.