Well, I tried this "aerofred.com" site and well... I had lots of issues. What a bummer as it looked like an answer to what many seem to be asking about: plans and drawings.
1. If you are unregistered there is no search option on the site. You can sort, i.e. boats, planes, etc., but no search for a particular item.
2. The "register" experience on a mobile phone is horrible, small boxes show only partial info and no way of seeing the password ("*****"). Constant errors with the verification process.
3. You can find a specific item ("Schaarhorn" in this case) by using Google search as "aerofred.com Schaarhorn" and you should get to the item. However... (next)
4. You can't access any thing usable unless you register and that can be the next step in frustration, even on my PC.
5. If you are lucky enough to register when you want to download the free pdf - WOW - you have to download two applications to get anywhere (I assume., I decided to interrupt this process and uninstall the apps >>>). I looked those up and the were considered "do no harm to your computer" but do take over browsers.
(NOTHING LIKE INSTALLING SOMETHING YOU MIGH REGRET HAVING.)
This was way to much for me to continue with, perhaps someone else might do better. I found this very suspicious having all this to just download some free pdf files.
More reading on "OneLaunch" found on Reddit: While not specifically malware, the actions and liberties it takes on a computer is very close to it. This what is called a browser hijack tool. They effectively force ads and search results from their "partners" to drive traffic and such to them. Desktop toolbars are nonsense software now. No one needs them for anything and will often be told they need to download and install it to proceed with whatever they are doing.