The Pentagon UFO 2021 seems to manipulate its local vacuum (see Alcubierre mist cloud) and UFO inertial change.

Alcubierre's mist cloud around the Pentagon UFO, seems to be the a sign of the oscillating vacuum propulsion system.
https://bigbang-entanglement.blogspot.com/2021/05/alcubierres-mist-cloud-around-ufo-seems.html
Even Magnetic UFOs seem possible: see
"Different Levitation Systems Observed in Big Basin UFOs, EMEC and Anti Maxwell Effect and Free Energy.
see: https://vixra.org/pdf/2006.0130v2.pdf
and see: https://bigbang-entanglement.blogspot.com/