Jeff Merkley, a Democrat from Oregon, and Republican John Kennedy from Louisiana, have sent a joint letter to eight major US carriers wanting to know whether these cameras could be used to monitor passengers and under what circumstances they could be activated.

They've also put forward a bill that would prevent airline screens on aircraft in the future from having any embedded cameras or microphones.

Embedded cameras on planes came to light earlier this year when Vitalty Kamluk, a passenger on a Singapore Airlines flight, spotted a tiny lens in his in-flight entertainment system and posted a picture of it on Twitter.