Well for starters I did find out in Greece that their version of TSA will give you a free ride in a policia car when they find your dive knife in your "checked" baggage :(
I had a dive buddy who should have taught a class on packing, she got all of her stuff for a two week trip to Coz into a backpack with her fins tied onto the outside of that backpack with her exercise bands.
The only issue is bottles of sunscreen or insect repellent, pony bottles and line cutters.
If you can get all of your gear in a carry-on I’m impressed, my carry-on is just my photo gear and dive computers.
Dry you gear before flying, the damp weight has actually put my bag over the weight limit :(