Sam,
In a former life, I used to ferry a lot of gasoline to remote locations in jerry cans; we used both plastic and metal cans. We placed them underground and used them as refuel sources for a fleet of Single Cessnas. I carried them in 172's and 206's and 207's.
If you're going to carry fuel, it should be bonded to the airframe, and it should be kept secure. Use caution about building up vapors anywhere that a spark could occur. Remember that sparks occur via static electricity, which occurs naturally in the airframe (especially if bonding between static strips and the airframe isn't good) in flight, as well as on carpet or with movement of the fluid in the can. This can be especially true in synthetic fuel containers.
If you do carry fuel inside the aircraft, bear in mind the hazard it may pose to you as a missile and a source of fire in the event of a forced landing, and be mindful of that fuel any time the temperature rises inside the airplane. A riing temperature means increased fuel vapor. Keep fuel cans full. Empty containers are more dangerous than full containers. An empty container, especially on a seat or on carpet, without any bonding to the aircraft structure, can be a real threat.
Before you carry that fuel, ask yourself if you have any other choice.