hazardous conditions. pilot planes could be a $400 billion a year global business. why not passenger flights? first, the airline industry has remarkable safety record despite high profile disasters. many believe on board pilots remain the most reliable way to handle problems and retrofitting planes would cost billions of dollars. second passengers may not be ready. there are questions about reliability, questions about what happens if plane like this gets loose from its electronic teether and what is terrorists take over a ground station and take control of the plane. one would be having multiple ground stations controlling them. even then what if you have a hacker that takes control. all of these questions have to been answered even as the planes grow more automated.