Project Loon 20KM LTE transmission from Regular Handset
Far field EM waves don't stop propagating until something absorbs them or changes their direction - that's  why we can observe stars. Range problems on the ground come from curvature of the Earth and accidental shielding that occurs in various objects and structures. 

Radio is a lot like light, except that many more things are effectively transparent to radio. Due to some other physics problems, though, passing through an ungrounded metal structure destroys the original signal and repeats it with less than optimal conditions, leading to problems on the ground. Passing through a grounded metal structure can destroy the signal entirely.

Project Loon is a practical method to take our best wireless broadband technology and lift it to where it has better line of sight to consumers.