You can bring them on as carry on's and stow them but the kids can't sit in them. Booster seats (or any CRS without an integrated harness) are not approved for airline travel. If you want to use a CRS on the aircraft check for a sticker on the back indicating it can be used onboard, the FA's will!
IMHO if a child meets the height/weight requirement for a backless booster then they meet the height/weight requirement not to need a CRS on the airplane.
Save Up to 30% on Rooms at Walt Disney World!
Save up to 30% on rooms at select Disney Resorts Collection hotels when you stay 5 consecutive nights or longer in late summer and early fall. Plus, enjoy other savings for shorter stays.This offer is valid for stays most nights from August 1 to October 11, 2025.
CLICK HERE