Well, Chris, I hate to say, "You get what you pay for," but you do.

Most of these cheap planes have all the electronics on a single board, so you can't really take the usual measures of rearranging components, checking connections, and whatnot. Unless something on the board is visibly smashed or burned, a casual inspection isn't going to yield any answers, either. An electronics expert might be able to troubleshoot individual components, but without a schematic he'd be dead in water too. Getting the schematic is not likely, since it's proprietary information and "throw away" electronics. Not to mention, the company probably never anticipated anyone ever wanting the schematics, so you'll get "Hunh?" when you call and ask for them.

There are a couple of things you can check. Make sure the battery is fully charged first. Sometimes what will look like glitching will be caused by a low battery. It could also be the motor sparking internally. Make sure the connections to the motor are good, and that the motor has three capacitors installed on it.