the "bull dog dart" is my favourite paper air plane fly's well and can work as a glider or a dart!
Step 1: Fold #1
first fold the paper vertically then unfold. you should see a seem in the middle of the paper.
Step 2: Fold #2
fold the corners to the seem
Step 3: Fold #3
then fold the corners down to the seem again
Step 4: Fold #4
fold the top (should be pointy) down with about an inch left.
Step 5: Fold #5
fold in half vertically
then fold the top part of the air plane down about half way.