Start with a rectangular sheet of paper
Fold the paper in half lengthwise
Unfold it
Fold the top two corners down to the center crease
Fold the new top edges down to the center crease again
Fold the plane in half along the center crease
Fold one side down to form a wing
Flip it over
Fold the other side down to form the second wing
Adjust the wings evenly
Bend the wing tips slightly upward if desired