“I have been making and flying models airplanes on and off over the years since I was 7 or 8, mostly balsa and tissue models. with the improvements and lower costs of batteries, motors and radio gear, I have been to make foam airplanes that i could only dream about most of my life. Once i started again with the airplanes, i discovered the quad copters and FPV, both with and without GPS. requiring an ID tag on each aircraft is a good idea, but requiring transponders will only make flying unavailable again. I do not think it will stop the few people that want to cause harm or trouble from flying, because they will do it without the transponder. but it will stop the hundreds of thousands of people, friends and family’s that love flying and the hobby. Let alone all the teaching and learning of aerodynamics, mechanics, electronics and safety that will be lost. Bill Kruse Cary, IL”