One critical dimension not mentioned often is the bag depth for carrying large lenses like the 500 f4.
The inner dimensions:
ID: 13” W x 6.5” – 7.5” D x 18.5” H (33 x 16.5-19 x 47 cm)
18.5x7.5" ought to do it.
From a review on the TTank website for a Airport International:
I use this frequently when traveling, and it's a back saver! Last trip I had two D2x bodies, 80-200, 24-70, a fisheye, two flashes, misc stuff - along with a 400/f2.8. It's able to carry my briefcase with laptop - and best of all, I don't have to carry it. It fits easily on large planes, and even manages under the seats on most regional jets. I've had no trouble with the handles, locks or zippers - it's rugged. By now I think it's got about 200,000 miles and about 50 trips, and it now occurs to me that it looks pretty much as good as new except for the wheels themselves. Pretty typical ThinkTank product - not a lot to complain about. The only thing I'd improve is the divider system - it can be a bit of a puzzle to configure it.