Stuffed animals, in particular, are a great example of a toy that's usually okay to bring on a plane. After all, who doesn't love a good cuddle buddy during a long flight? Just be aware that if your stuffed animal is particularly large or bulky, you might need to check it in your luggage instead of carrying it on.
A good rule of thumb is to think about whether your toy can fit in a reasonable sized carry-on bag. If it's a tiny figurine or a small stuffed animal, you're probably golden. But if it's something enormous, like a giant teddy bear, you might need to make other arrangements.