This is a short list of some things that apparently aren't allowed onboard any domestic or international flights in the US, taken directly from the TSA website

1. Knives
2. Box cutters
3. Ice picks
4. Swords
5. Spear guns
6. Cattleprods
7. Kabutons
8. Nunchakus
9. Throwing stars
10. Dynamite
11. Hand grenades
12. Tear gas
13. Snow globes

So I guess if you're planning on hearding cattle, honing your fencing skills or are Michelangelo, you'll have to take the train.