The bodies of two people were found in a landing gear compartment of a JetBlue plane at the Fort Lauderdale airport in Florida, according to the company.
The two deceased people were found during a routine inspection on Monday night after the plane landed, JetBlue said.
"The circumstances surrounding how they accessed the aircraft remain under investigation," the company said in a statement.
"This is a heartbreaking situation, and we are committed to working closely with authorities to support their efforts to understand how this occurred."
The Airbus flight came in from New York's John F Kennedy International Airport, departing at about 20:00 local time (01:00 GMT) on Monday and landing at about 23:00.
Local police are investigating how the two people accessed the plane, while a medical examiner's office is performing autopsies to determine their causes of death, according to the BBC's US partner CBS News.
The incident comes just two weeks after a body was found in the landing gear compartment of a United Airlines plane, which landed in Hawaii on Christmas Eve. Officials have not shared how the person got into the landing gear compartment or what the cause of death was.
The landing gear compartment of a plane is a dangerous place, exposing stowaways to extremely cold temperatures and a lack of oxygen. Those inside the compartment can also be crushed by landing gear when it is withdrawn back into the airplane.
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