Overlooked but not unloved — They skip through the air in a stop/start, rise/fall, quick/slow, tango/rumba/salsa type of flight. Their motion gives them the common name of Skippers. Oh, to be sure, some are called Darts and Darters and Swifts for their no nonsense A-to-B flying. But most have this fluttery way. More than 3,500…