[MQAAord]

Since there is no shoulder belt with an airplane seat belt, the lap belt is adequate for a 6 year old. Make sure the lap belt is tight over the hips, not up on the stomach (this is true for all pax, not just kids). The reason booster/seat positioning devices are used in cars is to help properly position the shoulder strap on smaller kids' frames.

You can use a car booster seat, but ONLY if it is a one-piece unit with a solid back. Booster type seats that are only a bottom piece are NOT approved for aircraft use (this has to do with aircraft seats' break-over feature). Check the label on the carseat for the words "approved for use in motor vehicles and aircraft".