Kingfisher Airlines has lost its flying permit after a deadline to renew its suspended licence expired, India’s aviation regulator announced.


The debt-ridden carrier has been grounded since October after repeated strikes by workers over unpaid wages.


The airline said there was no cause for concern as rules allowed the renewal of a permit within two years of expiry.


Kingfisher has $1.4 billion in debts and it is looking to raise funds after lenders refused to give fresh loans.


“Kingfisher’s flying permit has lapsed,” news agency AFP quoted the Directorate-General of Civil Aviation (DGCA) chief Arun Mishra as saying.


“They failed to provide additional details on the funding of operations,” Mishra said, referring to Kingfisher’s revival plan submitted to the DGCA last month.


The airline said it was “confident of securing approval from the regulator on the restart plan, licence approval and reinstatement of its operating permit”.


The carrier recently said it was in talks with Etihad Airways and other investors to take a shareholding.


Some reports said that Kingfisher planned to sell a 48% stake, though the firm did not confirm the claims.