If there's some reason you can't or don't want to carry the Wii on the plane, you can check it with a starter pistol. You can get one for under $30.
Don't do this before reading and understanding the details. You'll also need a locking hard case, large enough to hold the Wii and your starter pistol.
Or don't bring it on the plane at all. Ship it FedEx or UPS, where it can be tracked and insured against damage or loss.