ORIGINAL: Flak
My son has a PZ P-51D and flies the crap out of it. His little P-51D flies the pattern along with the fuel powered planes. I must say I'm not a fan of electric planes, but I am impressed with the performance.
I have one of the Mustangs in stock configuration. And there is no way it would keep up with the glow planes simply flying the pattern unless the glow guy was pulled way back on the throttle. Has your son's been modified?