<blockquote>Ultimately, though, the fact that we use fixed-wing aircraft today is a good indicator that flying saucers, while cool, just aren’t that functional. If flying saucers were somehow faster or more efficient or capable of lifting heavier loads, we would almost certainly see them in a commercial setting. Sadly, while some UFO sightings may have indeed been Project 1794, it’s unlikely that they were anything more than experiments carried out by humans, not aliens.</blockquote>
via <a href="http://www.extremetech.com/extreme/137505-us-air-forces-1950s-supersonic-flying-saucer-declassified">US Air Force’s 1950s supersonic flying saucer declassified | ExtremeTech</a>.