Let me take a picture of you and your paper plane!

Paper folding became popular within a century, approximately 460-390 BCE. It is impossible to ascertain where and in what form the first paper aircraft were constructed, or even the first paper plane's form.
For over a thousand years after this, paper aircraft were the dominant man-made heavier-than-air craft whose principles could be readily appreciated, though thanks to their high drag coefficients, not of an exceptional performance when gliding over long distances.
With time, many other designers have improved and developed the paper model, while using it as a fundamentally useful tool in aircraft design. One of the earliest known applications in compound structures and many other aerodynamic refinements to modern paper planes was in 1909.