The passenger noticed the camera while on a flight from the United States to Tokyo in September 2018, and others have since also noticed the cameras onboard American Airlines flights.
The airline told BuzzFeed News that cameras are integrated into some of the in-flight entertainment systems on its aircraft, but they were deactivated.
"Cameras are a standard feature on many in-flight entertainment systems used by multiple airlines," the company said.
"Manufacturers of those systems have included cameras for possible future uses, such as hand gestures to control in-flight entertainment."
American Airlines said these cameras have never been activated, and the company is not considering using them.
Just found this interesting sensor looking at me from the seat back on board of Singapore Airlines. Any expert opinion of whether this a camera? Perhaps @SingaporeAir could clarify how it is used? pic.twitter.com/vy0usqruZG
— Vitaly Kamluk (@vkamluk) February 17, 2019