Two pilots flying near Dallas-Fort Worth Airport recently reported mysterious lights behaving strangely in the sky, reports coasttocoastam.com.

The incident, captured in an air traffic control conversation, occurred last Saturday as their flights approached the airport.

The exchange began when one pilot asked the controller if any military operations were happening nearby. The controller responded, “It is cold. I’m curious, why do you ask?” The pilot explained, “It’s gonna sound a little weird,” and described seeing “two lights… jogging back and forth” above their aircraft.