Vistara, co-owned by Tata Group and Singapore Airlines, has been hit with a number of flight delays and cancellations over the last few days, the airline said on Monday.
The airline said its teams are working to stabilise the situation.
"We confirm that we have had a number of flight cancellations and unavoidable delays in the last few days due to various operational reasons," said the Vistara spokesperson.
"Our teams are tirelessly working to stabilizing the situation. We regret the inconvenience caused to our valued customers due to these disruptions," the spokesperson added.
The irate passengers took to internet to complain about the long delays.
"#Vistara #UK827 Bombay to Chennai delayed more than 5 hours and no confirmation yet. Absolutely pathetic," Vignesh Murali posted on X.
"I'm seeing many such complaints about Air Vistara in the last two days... Wonder what's wrong. Some said pilot/crew shortage," posted Swaying Sayings on X.
"Yes, too many complaints. Can @vistara be more honest and tell its customers what is wrong, how long, cut flights with notice, and restore credibility? Too much of lies now. People trust vistaara, getting damaged, @JM_Scindia," posted TV Mohandas Pai, Chairman, Aarin Capital Partners.
"Another Vistara flight delayed by an hour!. They have really adopted the Air India culture well," said Anshu Mor, a stand-up comic.
Historian and writer Vikram Sampath posted his flight was cancelled last minute.
"Pathetic @airvistara ... mumbai blore flight 5 pm gets cancelled last min citing "operational reasons".. we change booking to morning 9 am. U announce boarding n then say "operational reason" it now leaves at 11. Do u even care for ur customers, their time, money? As a CV Gold member frustrated by ur poor service," posted Mr Sampath.
Early in March, the flight operations of Vistara were impacted at Delhi and Mumbai airports, mainly due to the non-availability of pilots.
Vistara is in the process of merging with Air India post its privatisation and Singapore Airlines acquiring a 25.1 per cent stake in the once state-controlled airline.