The operating airline is the carrier that physically operates the flight—it’s the logo on the aircraft you’re flying on. The ticket number typically begins with a 3-digit prefix known as the plating or validating carrier code, such as 016 for United Airlines.
In some cases, flights are operated by a partner airline under a wet lease agreement. In these situations, the airline operating the flight is referred to as the ‘metal operator,’ while the marketing or ticketing airline is the ‘parent operator.’ For example, SkyWest Airlines (OO) may operate a flight on behalf of United Airlines (UA). In this case, OO is the operating carrier, and UA is the parent carrier.
Operating Airline