Flightradar24 has a nice interface and apps but it is CENSORED. Not all airplanes transmitting ADS-B are visible there. Fortunately there is https://www.adsbex

Flightradar24 has a nice interface and apps but it is CENSORED. Not all airplanes transmitting ADS-B are visible there. Fortunately there is https://www.adsbexchange.com https://www.adsbexchange.com which offers unfiltered data. You can set up a receiver so that it runs dump1090 separately and forwards it to both using Beast protocol. You can also participate in adsbexchange M-LAT.