Has anyone actually seated a toddler in a car seat on a flight? We're flying with DS2 (will be 2.8, v small for his age) and the thought of lugging his massive, heavy seat onto the plane and (if it fits) installing it etc makes me feel ill. He'll have his own seat. We're on easyjet.
Does anyone bother with this? Legally, do we have to? I guess these rules do exist for good safety reasons...