@cplist Windy itself is a leaflet plugin. And there is boat tracker tutorial (https://api4.windy.com/examples/boat-tracker/) where you can see how to add leaflet polylines, leaflet icons. In other tutorials you can see also leaflet popups... And you can also add leaflet layers (you are right there is currently no tutorial for that, sorry). I am not able to say if it works with leaflet-velocity, but you should try it. It probably will work.
C