Being on scholarship does not improve your chances at earning an Enrollment Allocation. This is because it is not a factor at all; EA boards are scholarship blind. The only criteria are your Commander's Ranking, GPA, SAT/ACT, and FA. I can tell you that if you were good enough to earn a scholarship, you are probably good enough to earn an Enrollment Allocation. From time to time, the AFROTC may also hold Foreign Language boards for those majoring in critical foreign languages.
You academic major is a factor; AFROTC cadets are split between technical majors and non-technical majors. These majors compete in different boards for EAs. Historically, the technical major has had a higher selection rate than the non-technical because tech majors board before non-techs. However, a non-technical major may end up with a higher GPA by virtue of their coursework and be more competitive come selection time and down the road. If you want to be a pilot, for rated selection your academic major does not matter.
Intended career field has an impact on selection. If you intend to volunteer for rated duty (Pilot, RPA, CSO, ABM) you are boarded separately regardless of academic major. If you are pursuing a career as a nurse, you are boarded separately.
The Air Force only commissions Active Duty officers. There are instances where they may consider commissioning cadets into the guard/reserve such as during force reductions or extremely sub-par performance as a POC.
