The airlines have loosened their restrictions on what you can carry onboard, but you still need to check weapons
Yes, this includes harpoons.
Not that you can do much with a harpoon. You’ll need a clear aisle for a good harpooning, but killer whales usually strike during feeding sessions. Which is when flight attendants are out with the beverage cart, blocking your throw.
Sitting next to a rampaging killer whale? You’re probably getting crushed against the window.
God forbid you’re trapped in the middle seat between two of them. Whatever happened to the airlines making oversized passengers buy two tickets?