I flew last March Milwaukee to Denver with a vexilar. Carry on! I called TSA in advance of the flight and there was no issue. They recommended having it in plain view and separate it from your other carry on items. No need to pull the battery. Just have the terminals disconnected.
No major issues. Take it out of your carry on bag and run it through the scanner on a separate tray. They asked a ton of questions and did the explosive wipe down. Took me an extra 5 minutes at most for the flasher. Now, I strongly urge you to put any plastics and Gulp in your checked in luggage. I set off a panic attack and was escorted by 3 agents to the little glass room and caught the third degree about my possible c4. Apparently, Flukes and gulp look like C4 in the scanner. That was a Holy moment as they dumped my bag out, had me surrounded, and went through everything and swabbed it all down. Remember, many TSA employees don’t fish and have no idea what you have there.