Kingfisher Airlines has been given a "no objection certificate" from oil companies and some aircraft leasing companies to restart operations, a senior regulatory source said on Wednesday.

Kingfisher shares extended gains to 6 percent on the news.

The airline, which lost its operating licence at the end of 2012 and has not flown since the start of October, has not secured approval from airports to fly again, the source at the Directorate General of Civil Aviation (DGCA) said on condition of anonymity.

Kingfisher, which is estimated to owe $2.5 billion in debt to banks, staff, vendors and others, has submitted a $119 million revival plan to the regulators. An official at the DGCA said last week that the plan would not be sufficient to rescue the airline.