Out here in Texas we get a lot of performance loss out of the engines, heat sag, especially glow engines. In the summer heat with temperatures going well over 100 degrees F and humidity exceeding 50%, the engines just won't run well at all. Some days you wind up running the engines extra rich and they just don't have much power. If you tried to tune them more lean to run better, they just overheat on you. So if you hadn't overpowered your plane to start with, you may not be able to fly it.

Electric planes can have problems too. The electronic speed controls can get hot enough to trip their temperature overheat circuits or logic and the ESCs will refuse to run the motors.

Gliders would have been a good way to go, but when it gets hot like it does, the thermals all but disappear on you too. But I remember one day having a glider stuck in the thermal zone about three feet off the ground. I could fly large lazy circles as long as I wanted to as long as the plane stayed about three feet above the ground. I had even watched some of the birds above in the sky and they couldn't even find a thermal either.

One other thought is the higher temperatures tend to reduce the lift as well, so a plane with a higher wing loading may exhibit wing stalling more when it is really hot outside.