If you get at least 15 days off (without too many lost to commuting) you can do what usmc-sgt and and I do, revolve your regimen around time at home.
I also work out on the road when it makes sense, but that's often limited to cardio and calisthenics, depending on what equipment is available. For my normal strength regimen, I need more than 50# dumbells but sometimes I use what they have a do a lighter workout.
On the road, always have the attitude that the work-out on any given day is optional, that way it's not hanging over your head if your day turns long. I can almost always work up the motivation to do an hour on an elliptical, that's way easier than intervals on a treadmill or calisthenics. And light/moderate cardio more than anything else will save your health and career in the long run.
I prefer to work out when I'm in the mood (which is not usually zero-dark-thirty), but I'll do it whenever I have to if necessary to fit it in.
I keep a list of hotels and what equipment they have, that way I can plan what I'm doing that week taking into account what's available on layovers. Also keep a list of running trails and public gyms near the hotels (I'm a member of one, and some others will sell you a day pass).
I always try to balance self-discipline with flexibility. If you're always working out when you'd rather not be, that gets depressing. Take a day off if you need to, life is busy.
If you get much less than 15 days off from flying, then you'll have to be pretty disciplined to stay on top of it in my experience.