The last thing you want to to hear while traveling at hundreds of miles an hour, tens of thousands of feet in the sky, is a mysterious noise.

But that is exactly what happened on an American Airlines flight recently. Emerson Collins, an actor and producer, recorded the creepy “moaning” sounds passengers heard over the plane’s public announcement system during a flight from Los Angeles to Dallas on Sept. 6.

And this wasn’t the first time airline passengers have encountered U.F.M.s or Unidentified Flying Moans (ok…we made that up).

  • Bradley P. Allen shared on Twitter that he and his wife heard “the moans and groans of someone in extreme pain” during an American Airlines Flight in July. The staff onboard the flight told Allen it had happened before, and they didn’t have an explanation.
  • Wendy Wanderman said she went through a similar experience while flying from John F. Kennedy International Airport to LAX on Aug. 5. She recalled the experience as “funny and unsettling.”
  • Doug Boehner shared that he heard peculiar sounds on an American Airlines flight in September, including a random “Oh Yeah” as the plane landed.
  • An anonymous user shared their experience with the Twitter user JonNYC:

“The flight attendants were standing by their phones … and the captain said that they don’t think the flight systems are compromised so that we will finish the flight to Dallas/Fort Worth International Airport.”

Twitter user JonNYC followed up with the anonymous user regarding their experience, claiming the sounds they heard were the same from Collins’ video.

“Ours was less aggressive. Although their volume might have been turned up more, making the sound more aggressive. It’s 100% the same voice. “

It’s unclear who – if anyone is responsible for the plane intercom takeovers. American Airlines is blaming the Sept. incident on a mechanical issue.

The airline says its intercoms are not connected to the internet and are hardwired, meaning it would be impossible for someone to remotely take them over.