Snakes on a plane!!

My brother, ever the airline buff, just spent twenty minutes of dinner conversation trying to figure out how the snakes on the plane in the movie Snakes on a Plane managed to get on the plane.  We tried to convince him that it was the point of the movie not to go beyond the plot point of there being snakes on the plane. He says it doesn't make sense. We said, we know, that's the point. He made an unhappy noise.

I agree with him. Though now I'm curious as to how they do get the snakes on the plane.

Damnit.