Answer:
the planes times in the air
Step-by-step explanation:
When a paper airplane is thown the path it takes is not the same every time. So, measuring the distance between the points where the airplane took off and the point where is landed would not show the time the plane was in the air.
The weight also does not determine the time the plane was in the air.
So, the planes air time recorded with the stopwatch gives the time the plane was in the air and will indicate the best plane.