No one at the airline was immediately available for comment, but an Air India official speaking on condition of anonymity said rats on planes were a "common phenomenon" worldwide and could "get in anywhere".
"They follow the catering vans into the plane when they smell the food," the official told AFP.
It is not the first time that India's loss-making carrier has suffered a rodent infestation.
Rats reportedly delayed a domestic flight from Mumbai by almost two hours in February, and in 2009 a flight to Toronto was delayed for 11 hours as staff tried to catch rats.
