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The 1510 with dividers is fine with the hood (at least with the 600 IS v.1), just the lid needs to be pressed down a bit the first couple times to close it while the lid foam is still stiff... I think Lars travels with the front lens cover on the lens, which with the 1510 will be a problem, as it adds additional girth to the lens.
So far for domestic US travel it's fit pretty much every plane I've been on down to the Bombardier Q400 NextGen turboprop (won't fit earlier versions of the plane), including the CRJs with 2+2 seating, though the crews of those flights might try to discourage you from bringing it on and gate checking instead. This is one advantage of the 1510, that gate checking isn't really an issue, compared to a soft sided bag option.
The 1510 is a great option if you plan to travel mostly in paved locations. The wheels don't have much clearance and therefore have a difficult time with rough surfaces. But airports, paved streets, sidewalks in good repair, etc. are no problem. I love it for traveling to sports events, but might have second thoughts about it if I was doing wildlife type work away from paved surfaces. It would be fine as a storage unit in a vehicle, but I wouldn't want to lug it around the woods.