The OpenSky Explorer supports filtering live air traffic (toolbox in the upper right corner). If you haven't noticed yet, the search field and the filter fields also allow using JavaScript regular expression quantifiers (see
www.w3schools.com/jsref/jsref_obj_regexp.asp). I opened this thread because I noticed that people compile pretty cool filters for visualizing certain air traffic behavior or observing fleets of interest.
If you have a cool filter, let us enjoy the experience as well and feel free to share it here
Here is one of mine, showing the USAF traffic which uses ADS-B: