> Cars move in a 2-dimensional space (surface), aircraft move in a 3-dimesional space (without costly highways), so you can utilize space way more efficiently a

> Cars move in a 2-dimensional space (surface), aircraft move in a 3-dimesional space (without costly highways), so you can utilize space way more efficiently and move more people per square mile. You still need to land planes 1 at a time, and that involves a clearing period between landings.