I have had 3 mid airs in the 30 years I have been flying, every time someone would ask, "who"s fault is it?" it amazes me. Like what was stated before, trying to mid air on purpose is much harder than it seems. I would have to say that mid air collisions are inevitable. It sucks losing your airplane for sure, my second mid air was a beautiful Cap 21 on its maiden flight, broke my heart but speaking from experience, it can happen. I hope you still keep flying and have fun, dont let this ruin your hobby in any way! BTW all 3 of my mid airs resulted in a total loss for my airplanes and the other guys landed with minimal damage. Recently we had 2 guys go up and purposly dog fight for quite awhile before they did manage to hit each other, they did not announce their intentions and one the airplanes landed right where flyers park their cars, while the airplane was spiralling down with power on, the guy never yelled or warned anyone his airplane was crashing, he had plenty of time too. Oh well at least nobody was hurt!