Just glancing at data at adsb.fi (which seems to run in background of airplanes.live) and it looks like airline planes send the wind data in ADSB. Using plugin to parse the data seems to me as not feasible, but I can see server side processing ideally paired with adsb.fi feeder that allows to get data from all aircrafts in one request every 30 seconds.
Processsing this data (probably not every 30 seconds, more like every few minutes) and extracting location, altitude and wind data is not looking to be hard task, question is how to get this data integrated into Windy plugin. Either by running own VPS and combining data from both, or if it is interresting idea to Ivo, they might even include it into Windy and use that data for Meteoblue/Windy themselves.