I have flown with my daughter last November and she was almost 3 at the time. She weighs about 33 lbs. I used her carseat. It is a pain in the butt, however, it is the safest way to travel and I needed it at my destination anyway. I would advise if you do go with a carseat the GO Go Kidz stroller attachment. It actually turns your car seat into a stroller and attaches and detaches fairly easily. It worked great. My other advice would be is to make sure that the airline you are using allows families with your children to pre-board. I had flown Southwest and where the rates are awesome, they have a new rule and only allow people with small children to board either in their A boarding group or after A group.....its awful...much better to be able to board before everyone else!!!