FNG. I've used the hopper as a carry on for the last few years and it has worked great. It's actually carried meat/fish all over the U.S. for me, plus Mexico and Canada and I've had no issues with it leaking.

Yes, you can use several models of the Yeti Hopper (specifically the Flip 8, Flip 12, and often the Flip 18) as an airline carry-on. The Yeti Hopper Flip 12 is the most popular choice for this because its dimensions (roughly 11.5" x 12.7" x 10") fit comfortably within the standard "personal item" or "carry-on" limits for most major airlines like Delta, United, and American. The Hopper Flip 18 is slightly larger and is generally accepted as a carry-on for overhead bins, but it is often too large to fit under the seat in front of you. Travelers frequently use these soft-sided coolers to transport perishable items, frozen breast milk, or even as a durable, waterproof gear bag. If you are carrying it through TSA, remember that the cooler itself is fine, but you cannot have loose ice or large ice packs inside unless they are completely frozen solid at the security checkpoint. If the ice has started to melt and there is liquid in the bottom, TSA will likely make you dump it out to comply with the 3-1-1 liquids rule.