The "absolutely gross" situation saw the Delta flight forced to make a U-turn about an hour into the nine-hour trip from Amsterdam to Detroit.

Passengers reported the back of the plane was left teeming with the larvae that it later emerged were emanating from a rotten fish.

"My family and I were in the row directly in front of the maggots," said one passenger, who goes by Nisha_16 on the forum Reddit.

"The lady right behind us told the flight attendants the maggots were falling on her head. I turned around and they were wiggling around on the seat... Absolutely gross."

The passenger added that one of their carry-on bags was next to the "disgusting" one, and that the suspected culprit was still seated and did not exit the plane at the end of the flight.

"I assume [there] are some kind of consequences, but unclear what", they added.

Another passenger, Kelsey, described her experience in a post on X.

She said she had complained about the "absolutely odd odour" on board, but that the "biggest disappointment" was the lack of attention from the flight attendants.

"They were all sitting around in the crew area laughing and talking when we had been on the plane for close to three hours with not even water offered," Kelsey said.

The 28-year-old passenger was put on an alternative flight but described the process as a "disaster" after she was stuck in Atlanta waiting to get home.

Delta - described as a "leader in domestic and international travel" on its website - confirmed rotten fish and maggots were in the bag and apologised to the passengers.

"We apologise to the customers of Flight 133 AMS-DTW as their trip was interrupted due to an improperly packed carry-on bag," the airline told Sky News.

"The aircraft returned to the gate and passengers were placed on the next available flight. The aircraft was removed from service for cleaning."

The plane returned to Schipol Airport at midday CET (11am UK time).

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The airline has more than flights 4,000 flights daily to over 300 destinations.

The airline has been hit by several incidents over the past year, including a nose wheel falling off a Boeing jet in January and severe turbulence on a flight last year leaving some passengers needing hospital treatment.