Transportation Security Administration is conducting a ‘far ranging’ investigation after an unticketed stowaway was able to avoid multiple checks to fly from New York to Paris.

The middle-aged woman went through a security checkpoint without a boarding pass at New York JFK and then evaded two further ticket checks before boarding a Paris bound flight.

The Delta flight was full so she apparently spent the duration of the hours-long flight in a bathroom undetected.

It happened during a busy day for travel just ahead of the Thanksgiving holiday.

An ‘exhaustive investigation’ is underway.

Delta Air Lines is cooperating with law enforcement and has opened its own investigation, the airline said.

“Nothing is of greater importance than matters of safety and security,” a Delta spokesperson said.

The stowaway hasn’t been named but is a US green card holder with a Russian passport.

She will likely be sent back to the US, an unnamed official said.

On landing in Paris, passengers were requested to stay seated while French police boarded the flight and the woman was taken away.

“I didn’t actually see the person in question. Apparently, she hid in a lavatory all the way at the rear of the aircraft when we departed JFK,” passenger Rob Jackson said.

“The first announcement to passengers that there was a problem was when we parked at the gate and they instructed us all to remain seated due to a ‘serious security issue.’”