A person messing with RF while in an airliner should probably be arrested, I agree with that part.
Probably best not to have the tool in carry-on, even powered-off, and I'd understand if TSA didn't permit that (like they wouldn't let a chef carry-on their knives, another tool with very legitimate purposes).
Messing with bluetooth on an airliner isn't going to do anything at all. If they were attempting to spoof GPS or playing with VHF signals that's another issue but the flipper isn't capable of that.
The TSA also doesn't care, they don't look for, and don't remotely have the training to detect suspicious electronics. Even if they did the flipper looks very innocuous unless you know what it is. You can reliably get much more entertaining things onto airplanes without them batting an eye.
It can do something. Many people depend on Bluetooth insulin pumps for instance, and in an airplane they may not have access to the alternatives in case the device stops working.
