Under the “Enter Airline Name Here” Box there are airline listed that have been out of bussiness for a couple of years and many new companies do not exist.
Airline with call signs have either a two or three letter identifier attached to the flight number. The three letter identifier is assigned by the FAA to a carrier. I belive the database used here on flight aware is a few years old.
Type in WWI72, WWI82, WWI36, WWI28 etc into the flight tracker box it will come up with the aircraft.
The operator for WWI is Worldwide Jet Charter which is not listed.