N6GN and K5PZB of the West Coast VHF/UHF WSPR Study Group are working to launch a 2m antenna at moderate altitude supported by a quadcopter and fed with a surface wave transmission line (SWTL). Beyond simply having a few minutes of flight time with a 2m antenna several hundred feet above ground level for a few tests, the longer term goal is to power the quadcopter from rectified RF transmitted up the line. This will hopefully produce an "active tower", something that is both a high altitude support and feedline for simultaneous operation of more than one frequency.
The power supply frequency is probably going to be 2m and may as well be WSPR at the same time. Some of the transmitted power can be peeled off to feed an antenna while the rest of it is used to power the motors in the quadcopter. However, with a suitable duplexer/triplexer, additional bands can share the feedline so that other bands might be operated.
Here is a video of the current prototype launcher with a 2m halo mounted around it. The final combination will include the coax and balun and weigh about 250g. https://groups.google.com/forum/#!topic/2-meter-wspr/DH5xMKVjcyc