Most manufacturers make play yards that are designed to move. Many roll on wheels and fold easily and compactly into their own totes, which resemble short golf bags (although less rugged), making them ideal for trips or jaunts to Grandma's. As we've said, basic play yards tend to be smaller (about 28 inches wide) and lighter (about 20 pounds) because they're not loaded with extras. If you can find a model that fits into its travel bag with its wheels exposed, it can make moving through a busy place such as an airport easier. The Chicco Lullaby LX mentioned above does that.
Nice to keep baby out of trouble at home. Once he became mobile we had to do an "upgrade" as we noticed he was starting to hit his head on the X shaped metal bars. We tried some alternatives but the best so far was wrapping the metal bars with pool noodles (see picture). You'll need 8 pool noodles and some cuts (buy some extra in case you mess up). Use 2/3 of a pool noodle to wrap the internal bars and the remaining 1/3 to wrap half of the external bar. The pieces will also need a longitudinal cut along the length to fit the bar in. You'll also need some small cuts in the middle of the longer piece to fit the center rivet, where the mesh is attached to the bars. We got the pool noodles at the dollar store nearby for less than $10 and since ... full review