NY reported the Airbus A321, flight number 1942, departed Charlotte, NC on Monday night and arrived at LaGuardia late Monday night.
Investigators have said that the fetus was about five to six months in development, and that the local medical examiner's office will conduct an autopsy for more conclusive details about the fetus, including how it died.
American Airlines referred all questions surrounding the incident to local police.
"Not only the passengers had access to this plane".
The New York City medical examiner is now investigating to determine the cause of death and will perform an autopsy, NBC New York reported. "No further operational impacts are anticipated for fliers", the airline tweeted.
A statement from LaGuardia Airport said flights at Terminal B may experience delays due to an "out of service aircraft".
The cleaning crew immediately contacted their manager, who in turn contacted law enforcement, Franco said.
The Office of NYC Medical Examiner issued a statement to PIX11, saying it is "investigating what we believe to be a human fetus found deceased on an airplane".
A spokesperson for the Queens District Attorney Richard Brown, whose jurisdiction includes the airport, declined to comment.
"They didn't tell us anything until we were already waiting at the gate", she griped.