Right now there is a big difference between the number of people that actually want to fly fighters and the number that are willing to put it down on their sheet following T-6's.
I went through UPT 22+ years ago and back then, just about everyone wanted a fighter. Competition was often cutthroat with each person constantly asking how you did on this or that ride.
Today, things have changed for a number of reasons. I just spent the weekend with the commander of one of the UPT squadrons and we were talking about how it has changed.
Here are a couple of problems with the current system. To pick a fighter you have to track in the T-38.
1) T-38 is definitely harder, the washout rate is significantly higher than that of the heavy track. You could have been the #1 student in the T-6's, and know that you will easily get through the Airlift/Tanker track. If you choose to go T-38's and you wash out. It's all over, you don't get to go back and go through the Airlift/Tanker track. You are removed from training. That can be an immediate career-ender for some. People that already have a family and a vested interest in definitely maintaining a job are often putting down the Heavy Track for this reason.
2) If you do get through the T-38 Track, your chances of getting a fighter are still quite limited. Right now the AF is selecting first assignment "Predator: pilots, MC-12 Pilots, and other assignments such as (I read in one of the posts above) AC-130's, etc. With the cutback in fighter wings as we draw down again, there will be very limited fighter slots.
3) If you get a fighter slot, there is a high probability that you will not stay in fighters, or flying, for your career. First, You will first have to get through FTU (initial training in your fighter). This can be up to 7+ months for fighters. If you wash out here... again, it can be game over. I saw several people wash out not to return to flying anything. Some, if they were lucky, were able to transfer to another aircraft... but it's a craps roll.
If you do make it through RTU, you will arrive at your first base as a wingman. Depending where you are, you can expect to be at that base for 2-3 years. When you PCS (Change bases), many people found that they were leaving the Fighter world to be ALO (Air Liaison Officers with the Army, Reaper (Unmanned aerial vehicle pilot, MC-12 pilot, etc). 6+ years ago, this wasn't a big problem, you went off did your tour in another weapon system, and then came back to your Fighter. Unfortunately, because of the drawdown, currently, many people are not returning to fighters. Once the Unmanned Vehicle guys have you... it is a fight to get back. If you don't return to the F-16 within 5 years, you will never go back as it required a a whole FTU course for an inexperienced pilot (which is where a lot of wingmen or new flight leads are after 1 tour). Bottom line - I saw several talented fighter pilots sucked out of the F-16 never to return.
The pilots at UPT will be straight up with you about all of these type issues. The bottom line is that if you select T-38's with the dreams of flying a fighter, you have a much higher chance of washing out, 2) If you make it, a small chance of getting a fighter. 3) If you get a fighter, you have a probably 30-40% chance that after 1 or 2 assignments you will be shipped off to the UAV world with a difficult road ahead of you to stay in Fighters for 20 years like we used to in the past.
The UPT Squadron Commander says that all these issues weigh heavily when it comes time to select which track you want to go. Now days you are really rolling the bones to get a Fighter and stay in it. If that is what you want, my best advice is do the best you can at every single thing you can. We used to laugh at quarterly awards and the initial schools like SOS (Squadron Officer School), etc. Nowdays, those are discriminators to a lot of things (such as if you are in a fighter, staying in it).
Hope that helps, this thread was kind of old, but I'm up and can't sleep so thought I'd throw a couple words in.
Cheers
Lego