Second the Polar Bear 24 recommendation. We travel with both the 24 and 48 models. 48 would not work as a carry-on but has been perfect for us as a checked bag. Never had any issues on 30+ trips with either size. For refrigerated items or breakable stuff we have found that a Polar Bear 24 inside of a Pelican 1610 hard-sided case is pretty much indestructible but we have a decent amount of luggage storage on the boat which may not be the case for everyone.