Oh yes, the gas/alcohol powered R/C planes can be very dangerous. Using your example, if an R/C plane meets a Cessna, the Cessna would win, unless it took a direct shot to the windshield. But if an R/C plane were to be ingested into a jet engine, lots of damage would ensue. Ironic, isn't it?
Oh, as a little tip, if you're working on an R/C gas engine, and you are doing a run-up on it, and you are adjusting the carb/mixture settings....don't wear loose clothing. I speak with experience!