Car Seats that Travel Well

Before I had a child, I saw some very smart parents, in the airport, with a car seat that became a make-shift stroller. It fit a toddler and rolled as if it was luggage. The child was safely (rear-facing) strapped into it and rode through the airport. I'm sure this sounds obsurd but I was curious enough to ask them and then checked out the company later. I no longer have the information and would love to find it. Does anyone have information on this?

I could also use comments on strollers that travel well. My husband's family is scattered across the country, as are our friends. The infant carrier and matching stroller (Graco Coach Rider) have served us very well but, he's outgrown the car seat. Now it's time to look at new car seats and a smaller stroller (for travel only.)