It was the perfect day for an electric air taxi demonstration — albeit one without passengers. On Monday, an electric aircraft from Joby Aviation took off from JFK Airport for a flight demonstrating the company’s future air taxi route to Manhattan. The aircraft — egg-shaped cabin, six tilt-rotor propellers, electric motor — made its way west along the Brooklyn shore before turning north toward the city. Approximately 14 minutes after takeoff, it touched down at the heliport at West 30th Street, completing its historic journey. You could tell it was a momentous occasion based on the number of references the assembled officials made to the 60-year-old animated television show The Jetsons . (I counted at least three.) But the demonstration was also an indication of the long road ahead before these electric air taxis start carrying passengers as part of a commercial ridehail service. Joby’s aircraft can carry five people, including one pilot, but for today’s demonstration, it was pilot-only.…