I don't see that at all. Any recent evidence?
Ditto. The Kitfox/Cessna 177 accident is the last one I can think of. En-route midairs cause a very small proportion of aviation fatalities. I share the concern re. the risks to GA if someone were to bring down an airliner but mid-air collisions with other small aircraft are fairly low on my list of concerns - well below the weather, carb-icing and all of that.