The dream of flying cars has been around longer than Boeing Co. has been making airplanes. Now a vision from the pages of Jules Verne is near enough to occupy the present-day plans of Boeing’s leadership.“I think it will happen faster than any of us understand,” CEO Dennis Muilenburg said in an interview. “Real prototype vehicles are being built right now. So the technology is very doable.” The new era of flying urban vehicles is close enoughfor the man overseeing jetliners and spacecraft to begin plotting what he calls the “rules of the road” for three-dimensional highways.