Insure them and chck them. Put the hard case in a duffel bag. A standard USGI Aircrewman bag is perfect for a 1600 hardcase.
I applaud your thought process that keeps you from dragging a Pelican case into the cabin as carry-on. It just makes no sense and is counterproductive.
If you pack your gear smartly in a padded carry-on bag, not only will your gear be under your eye, but with a litle bubble wrap and some inteligent handling, you'll have no chance of damaging anything.
Over many years, I have veered down the path of heavy metal u/w photo gear, but now find that I can take a point and shoot Olympus and with some "shutter anticipation", a close-up lens, and a small external flash, I'm good to go.
I understand tha you are knee deep in photo gear, but I say this as a caveat to those others who may be just looking into housed SLRs with armed flash heads... and more. Go slowly, look at what big gear like that is required for... maybe a close-up capable point and shoot will do you well. The big gear is excellent for wide and super-wides, great for iluminating larger areas from a greater distance (maybe 10' away and a 10' area versus a point-and-shoots meager 4' max range), but ow much of that stuff do you want to do?
Back to your topic, though... pick the stuff you want to check... maybe the housings? Carry the expensive part- the lenses and maybe leave the stripped bodies as checked bagage?
Do airlines have a prolem with Peican? No, but TSA views them with great interest because of their air tight apability. You figure it out. Contrary to common "common wisdom" there is very little incidence of theft from bagage. Such documented reports are very few and make great headlines, but are largely urban myth as to freqency. People might steal cameras, but aint nobody stealing SCUBA gear. If a baggage thief is lurking, they will only steal something that is easily concealed and has viable maket as a used item for resale. Regulators, BCs or an empty camera housing? Zero value. Damage from handling from a bad repack? A different story.
Insurance. Did I mention that? When you make the decision to play with big-boys toys, you have to play like they do. Insurance is a given. My point-and-shoot has no insurance. I check the Olympus housing and carry the little camera.