If you are looking to become a career pilot, you will want to go to college whether or not you join the military. Most airlines require a college degree these days. If you want to fly in the military, than you must be an officer which will require a minimum of a 4 year college degree. Andrew is correct in his answer, that a college with an aviation program, will get you into the commercial aviation world quicker than the military, generally speaking. However, there are some great opportunities in the guard or reserve components of the military which would allow you to fly in the military, and also as a professional civilian pilot. No matter what route you choose, I highly recommend a college degree if you want to be a professional pilot.