The approach I've been using:
- Do your best to pack your main rig in a camera backpack. Carry-on bags might still get checked at the gate for busy flights (and subsequently lost in transit), but the your "personal item" will always stay with you. For me, that'll usually be a D850, housing, 45 degree viewfinder, 2 Ikelite DS232 strobes, 28-70mm lens, a WACP-C, and some arm clamps for wide-angle destinations, or a 105mm + port + Saga Trio diopter for macro destinations. I can't fit float arms in the bag, but it's enough to do close-focus stuff in a pinch, though I do need to disassemble the viewfinder and arm mounting balls from the housing for everything to fit.
- For other lenses, ports, and other gear, try to pack them in a carry-on with configurable divider panels. I've found them to be enough that I don't need to bring bulky padded bags for my ports. I personally like the Tenba Air Case for this role because it's very sturdy, but not as heavy or as obvious of a target for theft as something like a Pelican case.
- Some airlines like Philippine Airlines weigh your carry-on bags as well, which you should keep in mind if that'll be a concern. If you're forced to fly with one, you may want to consider wearing a photo vest that lets you carry some of your lenses and accessories on your person instead of in your carry-on, though you should be warned that it might not be the most comfortable in a cramped airplane seat.
- You can save space by putting your camera body in your (unsealed) housing. I've heard some people expressing worries about potentially causing the camera tray to get misaligned from too much jostling - it's not something I've personally run into, but if you're worried, you could also pack a lot of accessories in there instead.
- Avoid leaving a lens attached to your camera body if possible, as you risk damaging the connecting thread if your packing job exerts force on the wrong spot