An A-10 is slow enough to track with a Cessna, and has a couple of tools to eliminate the threat if necessary.
No need to shoot anyone down, merely buzz right over them with about 350 knots closure and pull up violently just as you get to it. The downward wash off the F-15 would swat a 172 out of the sky.
Stall speed for A-10 is 138 mph. The Cessna is less than half that.