I'm going to make what will seem an odd suggestion: Desoto Triathlon Transition Pack. I bought my 2014 version for its designed purpose, but have used it a ton for travel as both carry on and checked baggage.

It holds a ton of stuff, has a lot of ways to separate and organize stuff and, for some reason, the transition design features seem to translate well to charter traveling.

It works great and the quality is top notch. I have no affiliation with Desoto other than I own a bunch of their gear and have interacted with their owner a few times on a multi sport forum I frequent.

https://www.desotosport.com/collections/accessories/products/transition-pack-v8-2017