American aeronautical engineer who spent his career at NASA Langley, worked on vertical take-off vehicles, and wrote the one book in this literature that treats reported UFO performance purely as an engineering problem: Unconventional Flying Objects: A Scientific Analysis, written in retirement and published posthumously in 1995.
What the book actually does
It takes the reported behaviour, the right-angle turns, the absence of a sonic boom, the hovering without downwash, the effect on vehicles and on witnesses, and asks what field would have to be acting on the craft and its surroundings for the reports to be internally consistent. Hill’s answer is an acceleration field acting on every atom at once, which removes the g-force problem and the shock-wave problem together, and he works out the consequences with the arithmetic of a man who designed real aircraft.
Why it matters more than its conclusions
The method is the contribution. Hill did not argue the objects are real; he asked what would have to be true if the reports were accurate, and then checked whether the answers were mutually consistent. That is the same move the benches on this site make, and it is the analysis Paul LaViolette’s UFO chapter in Secrets of Antigravity Propulsion builds on.
Connections
Secrets of Antigravity Propulsion · Paul LaViolette · Five Observables · Propulsion Configurations · Anti-Gravity · Metric Engineering · Michael P. Masters