This plane is commonly known as the Nakamura lock.
Step 1: Step 1
Take a piece of A4 or letter piece of paper and fold it in half long-ways.
Step 2: Step 2
Unfold and fold it so it looks like this.
Step 3: Step 3
Fold it down to look like this.
Step 4: Step 4
Fold the corners down to look similar to this.
Step 5: Step 5
Fold it in half to make sure the sides are even.
Step 6: Step 6
Fold the tip up to look like this.
Step 7: Step 7
Fold the sides along the middle fold to form the wings.