It was a perfect day for flying. Greg Zackney—who served as a Harrier pilot for the U.S. Marines before becoming a contract pilot for Icon—powered up the Icon A5, popped open my passenger-side window, and started out over Manhattan’s Hudson River. The propellers whizzed and whirred as we zipped across the water like a Jet Ski, quick and agile, making hairpin turns with the greatest of ease. Then Zackney straightened out and, at full speed, headed directly for the George Washington Bridge. Suddenly, we were air…