In all seriousness it sounds like a shadow projected onto a stratus cloud. It's somewhat non-intuitive to people that shadows do not grow in size with distance in the air. A 747 casts a 747 sized shadow onto clouds since the sun is so far away its light rays are all effectively parallel.

One thing that does happen to shadows is they get blurred at the edges (an aircraft won't completely cover the sun at a distance). An aircraft will tend to cast a vaguely "T" shaped shadow at a distance that's roughly the size of the aircraft. I can see a "t" shaped object in these images.

Here's a video of a test flight of the Vahana aircraft. https://youtu.be/S-5JeapSsbE?t=188

See the mysterious "t" shaped shadow it's casting? It moves erratically and doesn't match intuition of a shadow since shadows from the sun don't work the same way as indoors due to the parallel rays. You get these same shadows projected onto clouds as well.

The real kicker is that in these videos they both show and report that the shadow rotates when the aircraft turns! Like guys what the fuck do you think it is? Haha oh dear.