Your path doesn't effect your aircraft outcome, however, going through OTS in this day and age only gives drone slots, I haven't heard of pilot slots through OTS in years.
IIRC, only about 5% of USAF officers are pilots. Depending on your commissioning route, that will decide how you apply. USAFA & AFROTC work like this, you get in, and have to commit to joining the USAF before applying for jobs, and then at that point you might be selected as a pilot, it's not assured. In OTS, you sign up for your job specifically, and are guaranteed it so long as you graduate. The issue here is they don't offer pilot slots through OTS these days to my understanding, it's too coveted for ROTC to give to OTS. You can apply for pilot training while in another job, but it's a rough road to take, better chances than OTS though. With the Reserves and Guard, you sign up for your unit's aircraft, and your guaranteed that plane so long as you don't wash out.
Your aircraft are decided by your track, and proficiency. Someone outlined the old track system up there, but the new one condensed the prop track into the heavy track. Basically, you list your preferences, and the slots will be given by class ranking until they're gone. Tracks are fighter/bomber in the T-38, Heavy in the T-1, and helo in the Huey, which transitions you to Army UPT for the duration of that. It's harder to track helos than fighters, because there are less helo slots per class than fighters. Most people get stuck in heavies, thats where most of the slots are. If you track fighters, you'll probably get FAIPed (stuck teaching UPT instead of flying real planes), or sent to the F-16, the most common fighter.
To become an officer, it's anywhere from 4 years to 2 months, it all depends on your commissioning source.
To be a pilot it's ~one year for UPT the initial training, and about a year for your FTU, the formal training unit that teaches your specific airframe, but that varies alot based on what your fly. Also, you may have to wait a year between your commission and training while you await your slot, enjoy sitting on your hands butterbar ****wit.