I shoot a Nikon D700 (1.1kg). My travel lens is a 28-300mm (800g) so my standard camera kit comes in at 1.9kg. I actually don't bother to pack the camera anymore; I just strap it around my neck and start shooting the moment I get to the airport. The camera goes through the x-ray machine and on board I just put it under my seat or keep it on my lap. Sometimes I'll put it in the overhead but only if there's other stuff to keep it more or less in place while we're cruising.
This way the camera is always nearby if I want to shoot or take a pic of airplane food or whatever. When I'm touring, the camera is always with me and generally around my neck. I've replaced the standard Nikon strap with
a far superior Crumpler that better distributes and cushions the weight.