A clever camera case, designed for when you don't want (or need) a full camera backpack.
It'll take a camera body with attached lens and 1-2 additional lens + odds&ends, in a well-designed case that can then fit into a carryon or other luggage.
Like all Lowepro camera bags, it's very well designed. Pictured: holding a Canon R6 w/ handstrap and RF100-400mm USM attached. The RF24-105mm STM is adjacent.
Since I'm not a professional photographer, I just take my camera along for fun. When flying, that means it has to share my limited luggage space, and that gets challenging with normal camera cases, and the gear is much too delicate to pack it loose (at least I shouldn't).
This size of "Creator Box" fits into my normal carry-on backpack (that goes under-seat), taking up about 65% of the interior compartment. That's bulkier than the gear alone, but provides such easy access that I'm willing to try it.
In this case, I'll still need something to carry my camera around, but I could conceivably put the whole creatorbox in some kind of rucksack.
There's several sizes of these Creator Boxes, after trying "Large II" and "Extra Large II", I think this (Large) is the more practical size. the XL took nearly all of the compartment in the same backpack, but added room for several additional lens (or a slightly longer attached lens).
Everybody's preferred gear is different, but this case works for the gear I'm most likely to travel with these days, and thus is Recommended.