We're planning a trip to my home state, which requires flying. My SIL has a pack and play for LO to sleep in (she's 16 mo), but LO only sleeps well in the pack and play with an actual mattress. We have one, but we can't exactly check it for the plane ride up there. She sleeps on a mat at day care, so I'm thinking something like the bed below would work. Has anyone used something like this for their young toddler? How'd it go?