Only because they are lighter and slower. I'm sick of people complaining about how much energy an aircraft consumes. No traveler is willing to submit to a 4-hou

Only because they are lighter and slower. I'm sick of people complaining about how much energy an aircraft consumes. No traveler is willing to submit to a 4-hour airplane ride to travel a few hundred kilometers, yet this is an excellent way to give the airplane both better mileage and higher speed than a car. We could easily design a powered vehicle that has weight on the same order as a bike, while getting better mileage. I can just hear the customers queuing up to buy it: "A motorcycle with a top speed of 40 kph?" Perhaps this mindset is about to change. But I wouldn't bet on it.