Wireless Power Transmission
Do you think it is possible? Would it require only one transmitter, or several, spread across the globe? Would it be safe? Would it be worthwhile? Could Tesla's original spark gap circuit been sufficient to drive it? Or would it be better to use vacuum tubes or solid state setups? Would the operating frequency be very high or very low?
Pictured below is how I think Tesla may have done it, based on the information I've seen. It's a bit over-simplified, but to the best of my knowledge, it covers most of what is needed. Please note that, although the transmitter terminals would be at a much higher elevation than pictured, the receiving terminals could stay at a relatively low elevation.
This link is to a YouTube video of someone using a small Solid-State Tesla Coil for wireless power transmission: www.youtube.com/watch
Edit: I had orriginally imagined that the system would work by capacitive coupling between the Ionosphere and the coils. Afterwards I realized that electrostatic capacitive coupling will decouple after seperation between two plates is greater than 1/2 the wavelength (or, at least in theory), so I personally abandoned the idea. The only problem is that I can't imagine how power would be sent to airplanes.
Also, this is a very good read on the subject, from a very interesting site: www.teslaradio.com/pages/wireless_102.htm