I bought these because we've had luck with foam bumpers at home but they're not practical for plane travel. These are basically blow up thick pool noodles that you tuck under the sheet and they keep your kid from falling out of the bed. I was struck by the quality of the material, the thoughtful strip underneath that keeps them from slipping, and the enclosed pump to help blow them up. Once we arrived at our hotel, we installed them both within 5 minutes.
I probably wouldn't use these in your child's permanent bed because they will deflate slowly. And 3 pool noodles duct taped together are cheaper.