Like with all things, a ruck should be prepared for commercial flight the same as for any other luggage.
Tie everything down tight and if it has to go in a plastic bag, so be it.
Don't put anything valuable or fragile in it, or at least, in the outer pockets.
Leave the flammables, such as matches, fuels, hexy fuel tabs, out. Empty your canteens/camelbacks if they are getting checked-in, to reduce the weight and minimize the chance of it leaking. No pressurized containers. Put everything in ziplock bags. Coleman has great new self-vacuum-sealing camping bags, that are like big ziplocks, only you can squeeze all the air out and make it tight and small, and still waterproof. A great idea.
Batteries, and some pressurized containers are ok, within limits. If it's a common item, such as a shaving cream can, or a pair of flashlight or walkman batteries, there's no problem. Transport Canada only starts to worry when you've got boxes of lighters, large oxygen tanks (as for scuba diving), loads of batteries, etc. For most CF kit, you're good to go.
If you have doubts, don't bring it, or at least ask the airline.
Also, anything sharp or dangerous should be in the ruck or duffle and checked-in. We're in the army but god forbid we don't wanna hurt anyone! Joking aside, airline security is a big issue and the airlines don't care what you do for a living, they don't want knives and other instruments with hijacking potential on board in the passenger cabin.
Remember, finally, that the passenger assumes most of the responsibility and liability. If your ruck gets torn, dirty or broken, oh well. The general view of the airlines is that your luggage is there to protect the contents, and if it gets damaged but the stuff inside is ok, it's done it's job.