I thought this [0] explanation from a post a few days ago was pretty interesting. The idea being that the US gov is likely able to create a kind of localized plasma phenomenon with some interesting properties (i.e., “ would be circular, as seen from below, and oval, as seen from the side”.) Potentially useful for “radar spoofing.”[0]
All it requires is a powerful particle accelerator and a willingness to “[dump] a high energy proton beam into the atmosphere [creating] a glowing ball of plasma.”[1]
These balls of plasma could be coaxed to behave in very unusual ways, and would likely have a oval or round shape depending on a viewer’s perspective.
Lots of interesting and tangentially related bits on Bob Lazar/Area 51 (Bob has to stick to his story to stay out of jail, and Area 51/Groom lake is heavily associated with radar evading technologies like stealth, SR-71/OxCart, so experimenting with plasma balls by shooting a particle accelerator high into the atmo seems way more of a practical explanation than aliens or super exotic tech)
His idea that the ginormous black triangles that people have reported are also radar experiments is pretty compelling as well when compared to the alien explanation.
[0] https://www.otherhand.org/home-page/area-51-and-other-strang...
[1] https://www.otherhand.org/home-page/area-51-and-other-strang...