A Boeing 777 left Frankfurt for Bangkok on 21 August. It never got above 14,000 feet.
Ten hours of fuel on board and a full load, and instead of climbing out east it turned southwest and started flying racetracks over Saarland.
Two of them. Thirty five minutes. Altitude held to within five feet the whole time, which is not a person flying, that is an autopilot doing exactly one job very patiently.
Squawk 7700 throughout.
Then it stepped up to 14,000, turned, and flew a dead straight line back to Frankfurt. On the ground 74 minutes after takeoff.
We can show you every turn of that track because our stations heard it directly from the aircraft. We cannot tell you why, and we are not going to guess.