A 1/2 A plane with something like a Cox .049 is almost the equivilent of a small electric but the noise might irritate people. I have a Cox .020 powered Pocket Rocket that could easily be flown in the confines of a schoolyard but is sounds like the world's most pissed off bumblebee.

Before electrics and "park flyers" there was 1/2A and "schoolyard flyers".