This is pretty useless, but I found out how to download planes and create...... I'll just explain it, it is easier to do so

First what you want to do is create a .text file in your file manager

Second you would want to go to the plane you would want to download and get the link
And there would be a separate "download link" for the game to be able to download the plane.

Example the link to dazhang's USAF F-22A is https://www.simpleplanes.com/a/8tw7gd/USAF-F-22A

Then you would want to copy the text only right behind the "a/" in my case dazhang's USAF F-22A is "8tw7gd" once you copy that,
You go back to your file manager with the .txt file edit it paste "8tw7gd" ( or whatever your thing is ) and save and close it.

Then edit the name of the .txt and change it to .splane then save it

Then open it with with simple planes and then simple planes will start downloading that aircraft.....

Edit 2 :This is mostly useless, unless for some reason the website's download button don't work or this could be a way to share planes differently ( but it would still need to be uploaded on the website )

Edit 2 : maybe this could be away to have alot of different aircrafts in a .zip file where you could just unzip it and select which aircraft you want download with out having a bunch of links, and you could make it organized since you can name the it anything before the .splane with out affecting it