I use a LowePro Dryzone 200 camera backpack to carry things on to aircraft, this is a very nice backpack with a good harness and plenty of space for most needs. I can fit the following:
F100
F80
300 mm f4 lens
70-180 macro zoom
60 mm macro
105 mm macro
24 mm lens
Nikonos V
15mm UW-nikkor
Viewfinder for the UW-nikkor
Set of cokin P filter holders and some filters, adaptors etc
Olympus 3040
PT-10 housing for the olympus
SB 80 DX flash
Apple 15 inch powerbook
power adaptors for powerbook
headphones
cables to connect the olympus to the powerbook
Maha rapid charger and four sets of AA cells.
And it fits in to an overhead bin (or even under the seat in front on TAME airlines flight from the Galapagos to Quito
). You just need to practice looking nonchalant while carrying it, as I think all the above kinda exceeds the carryon weight limits on some airlines.
If I am carrying a lot of film, then the pt-10 housing has to ride somewhere else, usually in checked baggage wrapped in some clothes.
Large underwater strobes, arms, cords and my big housing used to ride in checked baggage, usually I wrapped the strobes in towels then packed them with a BC wrapped around them.
For your system as it stands you should be able to fit it all in to a daypack style camera bag and carry it on. There is a smaller version of the Dryzone (the 100) that may suit you. The thing that most appealed to me about the Dryzone is that it is waterproof when the zipper is closed, and allegedly will float while fully laden (I have not tested this
)