

It’s a program that uses an SDR to pick up the signals broadcasted by planes (ADS-B) containing their flight information. Then the data gets uploaded to an aggregator (FR24, Flight Aware, ADS-B Exchange) that gives a global view of all planes in the sky.
You can use the aggregators for free without uploading, but you get some perks for being a contributor. I just do it because it’s cool and I use the platforms for getting info on flights I’m taking (you can tell if your flight is gonna be delayed if the plane is delayed elsewhere for example).
Did you see the clip? It seems like an overreaction to me, he was slowing down but just happened to make the pass in the process. It’s honestly not THAT egregious IMO