A quandary is a state of perplexity or doubt, and people caught in one often devolve into depression or unhappiness. Our quandary today comes from the announcement of the Silent Air Taxi, a fixed-wing, hybrid-powered, box-wing aircraft. The quandary comes from whether it’s better to transport one’s self to a nearby small airport and hop on a low-slung commuter aircraft that requires only a 400-meter (1,312 feet, or about a quarter mile) runway. Or, to call up an on-demand Urban Air Mobility device, use the urban infrastructure and hie one’s self to an Uber SkyPort or a Volocopter launch pad. Its designers, mainly from Aachen, Germany’s academia and industry, point out that in Germany about 25-percent of the population lives within 10 kilometers (6.2 miles) of the 378 small and medium-sized airports that meet the Silent Air Taxi’s takeoff requirements. 50-percent of the population lives within a 20-kilometer (12.4 mile) radius of such an airport. If those seeking a quick …