I've seen stroller frames that are very lightweight that you can pop a carseat into. I'm not sure if I've ever seen one for a toddler carseat or a convertible infant/toddler carseat, but that's what I'm looking for. I don't need anything real high quality, the cheaper the better. I just don't want to have to lug both carseats, a stroller, both kids, and our carry-ons through the airport. I thought this way we could have a stroller and not have to lug the carseat. Does anyone know what I'm talking about and where I might look to find one?