How do I go about tracing someone I was at school with nearly 40 years ago?

Question:His father was in the American Air Force and posted to England. He came from North or South Carolina - just can't remember which.

Best Answer - Chosen by Asker: His father was in the American Air Force and posted to England. He came from North or South Carolina - just can't remember which.

I juggle between using www.peoplefinder.com and zabasearch. The reason is that peoplefinder gives an age and names of relatives, with cities. THEN I go to zabasearch, and have a better idea of which could be which.
Option 2 is tracing Dad, if you can remember his name. For starters, can you id the name of the English base, and work with that to find the specific air force unit? IF you can find the unit name, then work with military reunion pages. THAT is one way to narrow down Dad's age. If dad is now dead, then he should be in the social security death index, thus leading to find an obit. If your friend had siblings (guys are easier to work), you might also be able to find them.
The military angle can be real productive. I just spent a few hours, after finding reference to a history of the helicopter school that my former hubby was at in 1970. I was stunned to find his flight class picture, as well as other details of some of the classmates or friends that were in the service. All of this led to their reunion organization.
One more place to try would be www.genforum.com, which has surname areas. You COULD post a question there with names and reason for looking. It reaches a more targeted audience.

try Classmates.com

if you have the first and last name you can find anyone on zabasearch.com

Try Facebook, or typing his name into google. I've found a lot of old school friends this way.

Start with trying Classmates.com or Reunion.com Grams

That's easy: classmates.com.
Or, you can try to google the name, or use:
Finding live people:
Two good places I use are www.zabasearch.com and www.peoplefinder.com

If it has not been recommended already, you might try www.reunion.com or www.classmates.com. To do any detailed searching--such as for current address, email, etc-- it costs to join, but your school might be listed by someone else who may be searching for you. High schools and colleges both are listed.