I asked this question in a pvs thread, but re-posting to condense and ask my primary question. DS1 is 3 years, and hovers around 40 lbs. He's in a Como in our car. I don't really want to lug the Como through an airport when we next fly. We have a Scenera he still fits in height-wise, but may (or may not) be over the weight limit at any given moment. Can I still take it? What else are my options for over 40 lbs but still so young?