So we are flying with our 2 1/2 yr old to FL from Baltimore in less than 2 weeks. I don't want to carry his car seat because it is 1) very heavy 2) we are going on the DCL and won't need it for anything else. So question is: use the cares system or just the standard seat belt. I thought toddlers only had to stay in their seat during take off and landing so I'm not sure what's best. Thanks in advance.