Air India Flight 105 departed normally from Delhi's Indira Gandhi International Airport at 2.20am on Thursday with New York as its destination.
The Boeing 777 had only been in the air for around 30 minutes when the creature was spotted onboard.
The mammal was seen by crew in business class and flying between different sections of the plane, and the decision was made to return to Delhi.
Indian media reported that the aircraft was fumigated and the dead bat was subsequently removed from the eighth row of business class near seats D, E and F. The aircraft was brought back into service on Friday.
“AI-105 DEL-EWR returned to Delhi after departure after this local standby emergency was declared. On arrival, it was learnt that crew members saw a bat inside the cabin. Wildlife staff were called to catch and take away the bat. The aircraft landed safely at around 3.55 am,” an official at India’s Directorate General of Civil Aviation was quoted by local media as saying.
The tracking app FlightRadar24 showed that shortly after take off the 13-year-old Boeing 777-300 entered a holding pattern at 30,000 feet northwest of Delhi for more than an hour before landing in Delhi.
An investigation has been launched but an Air India official told IndiaToday that they believed the animal may have entered the plane when food was being loaded on board.
“The probable reason/cause may be loading vehicles like those for catering because all the time rats/bats come from their vehicle only,” the unnamed official was quoted as saying.