Can one person take out a car loan but have two people on the car's title?....If I am on the title my son's car insurance drops significantly but he wants to take the car loan out himself (to build credit)
Yes, but then either of you will need the other's permission to sell the car. I strongly recommend you get an agreement on that point, in writing, and possibly reviewed by a lawyer, before entering into this kind of relationship. (See past discussions of car titles and loan cosigners for some examples of how and why this can go wrong.)
When doung business with friends, treating it as a serious business transaction is the best way to avoid ruining the friendship.