Yes, you have to be an officer in order to be a pilot in any branch of the US military.
Not really. "Warrant officers" can be pilots in the Army. It's a different set of rules.
As for the rest of this thread, it's funny how a bunch of pedestrians are trying to tell a young pilot that he isn't a pilot just because he isn't yet allowed to fly passengers. The sole manipulator of the controls is the pilot in command, no matter what the piece of paper in his logbook says. There are lots of rules about under what conditions any particular person can legally act as the pilot in command, but legal or not the person responsible for manipulating the controls is the pilot. And if that person is alone or with someone who is unable to safely fly the aircraft, by default that person is the pilot in command whether or not they are certified or licensed for that position. A student pilot in the US is licensed to be pilot in command under restrictions set by his or her instructor, as outlined in the applicable logbook endorsements and in applicable FAA reglations. That time is usually logged as "solo", but for all practical purposes it is PIC time even if not logged as such.
It should be noted that ultralight pilots and LSA pilots often are fully licensed with less training and experience than a student pilot who is going for a private pilots license. It is simply a matter of training focus and CYA regulations that gives new ultralight and LSA pilots more legal authority in some areas than many PPL student pilots have.
