Many of these are sourced from the US Government, which means public domain. They also have links to the sources below so you can verify source and copyright.
This looks like a collection of clips from the Internet Archive. "General Aviation - Fact or Fiction" is on the Moving Image Archive at [1], and the full version is in the Internet Archive at [2]. Most of the content is from the Internet Archive. What's the point?
At least they don't slap their logo on public domain material, like Periscope Films does.
Depending on how they serve these clips (do they save them locally etc.) the point could be to take load off the internet archive.
The other point might be to provide better search capabilities than IA, also taking load off. Sometimes verifying something actually is Public Domain on IA can be work in itself, putting more work on a primary resource. In short it seems to me these people are doing a good thing.
At least they don't slap their logo on public domain material, like Periscope Films does.
[1] https://www.movingimagearchive.com/sources/general-aviation-...
[2] https://archive.org/details/gov.ntis.ava12749vnb
The other point might be to provide better search capabilities than IA, also taking load off. Sometimes verifying something actually is Public Domain on IA can be work in itself, putting more work on a primary resource. In short it seems to me these people are doing a good thing.