I am not a flight RN or Flight Medic (hoping for that eventually), but I am both a Paramedic and an RN.
Are you already an EMT?
Honestly I say Paramedic then RN because I was able to work full time while in nursing school only because as a paramedic your not constantly going, and unless you work in a really busy system, that leaves lots of time to study while your getting paid!
I also found nursing school A LOT less fun than paramedic school because it was A LOT more work with projects and care plans and other things. I did go to an associates paramedic program, so I had a lot of the general education type classes done which is a MUST for the nursing program, especially if you need to work whle your attending school.
The downside to being a medic in nursing school is that I found a lot of my instructors were harder on me and not as kind, I quickly learned to keep the fact that I was a paramedic quiet! Also it was really frustrating to go from being able to intubate and give meds etc in the field to going to nursing clinicals and having to be babysat while I flushed an IV!
I'll be honest I was bored to tears in nursing school, partially cause I HATE med-surg, and that is what nursing school seems to be all about for the most part. I am not interested in wound care or fancy daily dressings etc. Its just not me, which is why I started in the ER, and I have neve set foot on a med-surg floor, well except for clinicals of course, which I dreaded every minute of, especially having 1-2 patients... I'd would have rather gone to the dentist!!
So in the end the choice depends on you and your lifestyle, but I hope this information will help you make a more informed decision!