Open a blank Paint document to create a new guideline for your paper airplane project. You will duplicate the final airplane guidelines for multiple use, allowing for precise measurements every single time.
Select the line tool on the left-hand side of the screen to create your first guideline. In newer versions of Paint, the menu is more elaborate and located at the top of your screen. The line tool is near the middle portion of this menu, represented by a straight line.
Check the bottom of the page for the width in pixels of your current project. The first number represents the width and should ideally be smaller than the height. Divide this number in half to determine the absolute middle point for this template.
Click your mouse at the very top of the Paint software and pull the straight line down at the midway point. This is your basic guideline for the paper airplane, serving as the center folding point for this particular design.
Create a diagonal line from the top of your vertical guideline that extends down to the side of your Paint window. This diagonal guideline represents one of the folds that creates the nose of the plane. Likewise, you will create a secondary line on the opposite side of the vertical line. Make sure both of these lines touch the sides of the template on the same horizontal axis.
Create a secondary line that runs from the top of the center vertical guideline down near the bottom of your page. Make sure this line does not completely reach the bottom before touching the side. Additionally, create a mirrored line on the opposite side of the vertical guideline. These two lines represent the inner folds of the paper airplane's wings.
Save your current Paint document and make sure you can find the file at any time. Print out a test sheet and fold along each of the lines to check your paper airplane guideline for accuracy.