On a physical basis: Eyesight of 20/20 or better. There are height restrictions as well, these exist because the cockpits are designed so that all of the controls and switches can be reached by the pilot. If your too short, your arms wont be able to reach everything. If your too tall, your head will be in contact with portions of the airframe under certain situations. If I remember correctly in the US the height standards are 5'6" minimum, 6'2" maximum. Some individuals are disqualified from certain airframes due to their size even when they fall within the standard. During your initial Class 1 flight physical they will also make anthropological measurements to ensure that besides being within the height standard again, you will be able to reach all controls with hands and feet. Blood pressure is very important. Again during your Class 1 physical they will measure your blood pressure in a variety of conditions/positions. Very slight heart murmors (sp?) tend to DQ alot of folks. Basically, they are going to do the best job they can of ensuring that you will be physicaly fit enough to operate under the extreme stresses of combat flight, now and throughout your career.
On a mental basis: You will be subject to written tests. These tests are broken into various blocks. Again in the US probably about 40% of the written test is a psychological battery. They want to see what type of personality you are, exactly. Another block of the test involves spatial concepts. If you can't think and imagine in 3 dimensions your not going to be a successful pilot. You will also find blocks of testing involving simple aviation related questions. How do wings produce lift? How do the controls of the aircraft affect it? How the various flight instruments work etc. You will also find a section on what's known here as "speed coding". This is nothing more than a test of your ability to rapidly solve a series of alpha numeric riddles/questions in a very short period of time. With the speed coding block they count wrong answers against your score, as well as unanswered questions so 50 right and 50 wrong/unanswered equals a score of "0". They are looking or fast thinkers/problem solvers.
Personal basis: Finally, you will find yourself sitting before a review board of aviators. They will critique EVERYTHING you say and do during your interview. They watch your body language, are keen to perceive nervousness (not a good quality for a combat pilot) and judge things like speaking voice, eye contact etc. The questions will range from telling them your lifes story to "why you want to be an aviator" and everything inbetween. They want to see if your are a calm, problem solver with the ability to effectively communicate. You are not only be judged on your ability to fly, but in your ability to lead men into combat (you will be an officer) so they are interested in natural leadership qualities/tendencies as well.
Because of the cost associated with training a pilot, the selection process has become over the years very very critical. The Air Force (or other branches) have taken great pains to study past aviators and they now have a fairly accurate picture of the type of person they are looking for. They are looking for individuals that will not waste training dollars. That means they are looking for the type of person that will be able to go through the course successfully. Aviation courses are very condensed/front end loaded. Imagine earning your BS in 18 months and you will have a vague idea of how front end loaded these courses are. They aren't looking for the smartest guys, or the most educated guys, they are looking for the guys that can be shoved through a very technical course in the minimum amount of time.
You will also find the element of luck/fate/religion pertains to selection as well. There are limited numbers of slots, and being an aviator is one of the most prestigious professions in the military. In the US aviator selection boards occur on a once a month basis. Obviously beginning the selection process just prior to, during or right after the college graduation months (April through June) will put you in a group of highly educated selectee's. If you apply earlier or later the volume of selectee's will be down as will the overall quality. This can benefit you greatly if you are graduating with a bachelors degree because during April through June there are alot of master degree folks applying and all other things being equal, they will have an educational advantage over you in the eyes of the selection board. Again in the US, once a month the "approved and qualified" applicant packages go to the final review committee. The applicant packets are arranged in order of merit. If they are selecting 10 pilots that month, they will pick the top 10 packets in order of merit, the rest will be returned and have one more shot at the following months selection. If they are passed over a second time applicants will get a "thanks for trying" letter in the mail. In a perfect world, your packet will be reviewed at a time when they have the least qualified candidates with the maximum number of slots avaialable.
Final thoughts: There's not much you can do with yourself physically other than become as fit as possible. Things like height, eyesight and physical conditons you have no control over (heart murmor) can not be improved upon. If you can get your Air Forces physical standards you could go to your family physician and have him pre-screen you before you go through the trouble of applying. If you have a heart condition, the flight surgeons will find out I guarantee. Ditto for your eye's. You just can't sneak through these physicals.
Things YOU can do to make you a better candidate: Education. The military prefers science degree's over art degree's for obvious reasons. A BS in an aeronautical discipline will be given preference over a degree in history or literature. Post graduates have a much better chance at selection however BE AWARE OF YOUR AIR FORCE AVIATOR TRAINING AGE RESTRICTION! A masters degree is great but if your too old your too old. In the US the cutoff is age 26. I'd highly recommend you take a private pilots ground school course. This will cost you a few dollars but you will learn everything you need to know to pass the flight related portions of your written exams. Hope that helps, and good luck to you!
