Another option is to embed youtube videos on your own web page (hosted locally or whatever). You don't need to download the actual videos, the ads tend to be banners (not ones that make you wait to view it). Works great for my 4 year old.
Only thing about embedding is that videos can be removed at any time for any reason (or no reason at all). Plus having the downloaded videos make it easy to load up on an iPad or similar device for offline viewing on long trips where internet access may not be guaranteed.
Sometimes the ads can be very inapropiate for a 4 year old. I ended up installing Adblock just for that.
Well they are only banner ads, not video ads. But I'll admit I pay $10 a month for YouTube Red (actually they just renamed it Premium), which I get my moneys worth since I don't have broadcast or cable tv or netflix.
don't you still get recommended or autoplay started videos at the end of an embedded video? or is there a way to control that as well?