I don't think really the spinosaurus really swimmed in the movie, i think it was walking on the bottom on river. Then it jumped up on the boat. And if a spinosaurus,T-rex, or any really big carnosaur stepped on a plane wouldn't it crush it like he does in the movie.
from T-man, age ?, ?, ?, ?; July 20, 2001

TOM: Maybe you are right about the Spinosaurus walking on the bottom. Still, it must have walked onto higher river bottom in order to be standing as was later (with the crane).

Certainly any multi-ton creature like Spinosaurus or T. rex could crush a plane section by stepping on it. Biting it might not work, but stepping on it would.

Incidentally, scientifically speaking neither Spinosaurus nor T. rex are carnosaurs. The word "carnosaur" was once used for any big theropod (meat-eating dinosaur), but it technically refers to Allosaurus and its closest relatives. Spinosaurus was a spinosaur, and spinosaurs as a whole are more primitive than carnosaurs (that is, they branched off the family tree further towards the base of the tree). T. rex, on the other hand, was a tyrannosaur: tyrannosaurs are actually coelurosaurs, more closely related to dromaeosaurs (raptors), ornithomimosaurs, and birds than they are to carnosaurs.