Paper Aeroplanes- Measurement

In maths we have been learning about measurement. We have been learning how to estimate and measure. I made a paper plane marked out a runway with measurement tape. First we had to estimate how far my plane will go I estimated 1.5m but it actually went 1.6m it went further than I thought then we were allowed to make another plane for our second throw my second plane was a lot better than my first one I estimated that it would go 2m and it did go 2m I wasn't happy about because when I threw it for a practice it went 4 meters and when I threw it for real it failed.