I'm not sure about the weight limit of carry-ons, but I know that each ticketed passenger is allowed one carry bag.
Maybe their website would give more info as to the weight limit and the sizes.baggage info: carry-on
Following Transportation Security Administration guidelines, here are the new limits on carry-on items.
Guests are only allowed one bag to carry on and one smaller, personal item.
Personal items include things like purses, briefcases, cameras, food containers, or laptops (including the case).
Guests with disabilities are able to bring assistive devices on the flight along with their carry-on bags.
Song limits carry-on bags to 22x14x9 inches and smaller and must weigh less than 40 lbs.
Upon request, all guests and employees and their items may be thoroughly searched.
A car seat or other restraint for a ticketed child with a reserved seat is not counted as a carry-on or personal item, and can be carried onboard.
Federal law prohibits the following hazardous materials from being included in your carry-on bag: compressed gases, corrosives, explosives, fireworks, flammable liquids/solids, lighter fluid, loaded firearms, mace/tear gas, oxidizers, oxygen bottles, paints, poisons, and radioactive materials.