When I bought most of my gear I had a little travel in the back of my mind.
My dive bag came with this nice padded regulator-bag with a carrying strap which came right out of the outer pocket. It is perfect for carrying my reg, octo & computer onto the plane. I was actually very surprised that I wasn’t stopped or questioned at the security stop, but I guess they see this kind of stuff fairly regular. I also bought my BCD with travel as a consideration. I ended up with a Dive Rite transpac harness + the travel wing as it is small and round and fits nicely into my dive bag with plenty of room to spare. For that extra space I measured the area and hit the $.99 Store. I found a nice tupperware type container that fit snug in the space. In that I store my Mask(inside it’s own protective case btw), snorkel, dive lights, etc. Fins in the side pockets. Weights and tanks stay at home as they are supplied at every resort/boat or easily rentable.
Here’s the ironic part of it all. I bought my BCD with space in mind. But I’ll admit right now that it only gets me an extra inch of thickness inside my dive bag. But I’m more streamlined underwater so I’m happy with my choice anyhow. So next I pull out my 7mil wetsuit and replace with my warm water 3mil wetsuit. Oh wow! All of a sudden I have 3-4" of space to spare!! What the heck....I throw in some extra shoes and shirts to compliment my luggage. How convenient! NOT. When I got to the airport those extra clothes and shoes put my dive bag over the 50 lb limit. I ended up having to pull the clothes out and add to my daughter’s bag. The shoes I left at the airport.
The moral of the story....have dive bag will travel....but any BCD will do :-)