This is a simple little aeroPLAne. The included STL is printable as-is which you may be totally happy with and of course it doesn't have to be PLA. However, if you want to design and experiment with your own, you can.

How to Make Your Own
I built the model in OnShape. If you want to customise your own, you will need to get an OnShape account then just copy the workspace so you can change the values. The OnShape account is entirely free for personal use.

OnShape Model
https://cad.onshape.com/documents/81b6a822c08dfb60f036acf2/w/c8e122af81d67e90eaeae98b/e/6d342fa40865a8bbe6bac6dd?renderMode=0&uiState=69c65818efddfbbfe8c8c7ac

The model contains a lot of variables which you'll see on the left side,prefixed with (x). Experiment with those variable by changing their values and watch it update the model. Once you're happy, press the Right Mouse Button over "The aeroPLAne" in parts section on the left and export to an STL file.