The government's ambitious UDAN scheme may hit air pocket with the Mumbai airport authorities allocating only eight slots for the RCS flights.
The Civil Aviation Ministry had sought 20 slots from the Mumbai International Airport Limited (MIAL) for operating flights to unserved and under-served airports from the country's second busiest aerodrome.
"Since we have severe slot constraints and are unable to accommodate the request of even scheduled carriers for more flights, we could provide only eight slots for the RCS flights," a source said.
The GVK-AAI run Mumbai airport, which has become the world's busiest airports with a single-runway operations, handled 837 flights a day or one in 65 seconds on an average in fiscal 2017, taking over London's Gatwick airport that had 757 flights a day.
It handled 45.2 million passengers in the last fiscal, accounting for 18.6 per cent of the total air traffic in the country.
"We also have request from the government to provide slot for a flight to Shirdi airport, which is expected to commence operations soon," the source said adding that the Government is well-aware of the slot crunch at the Mumbai airport.
When contacted, MIAL spokesperson was not available for comment.
The 'Ude Desh ka aam Nagrik' (UDAN) scheme, under which airfares have been kept at Rs 2,500 for a one hour flights, is aimed at making the air travel more affordable and providing air services to the hinterland.
In the first round of UDAN bidding, five airlines won bids to operate on 128 routes connecting 70 airports, of which 31 are un-served.