Typically, a carry-on bag should not exceed 22 x 14 x 9 inches (inclusive of the handle and wheels). However, the rules can vary by airline. For example, American Airlines' carry-on luggage size is 22 ...
I feel about luggage carousels the same way I feel about head lice: avoid at all costs. These are the best carry-on suitcases for those who never want to check a bag again.