I have brought a fish in a bottle on a plane but that was before the liquid restriction. I would guess that they prohibit that now unless you stuff your fish in a bottle less than 3 oz. but then risk arrest for animal cruelty.

How about tires? Hawaiian Airlines prohibits checking tires http://www.hawaiianair.com/AboutUs/P...Item.aspx?cr=4 So does at least one unspecified Japanese airport (studded snow tires prohibited). http://search.japantimes.co.jp/cgi-b...0020126cz.html

I could call the airline but they might give the ok even if it's not ok.
Southwest allows 2 pieces free so you could transport 2 tires (if permitted) and take two trips to transport a set of 4. The person at the other end doesn't need the tires right away.

The size is ok. Diameter is 26" so length and width is 26. Width is 8" so add it up and get 61". Some big tires might be too big. As far as weight, the published weight is 26 lbs. The wheel is about 23 lbs so 49 lbs.