Which major airlines does Republic Airways operate for?

Republic Airways primarily functions as a regional airline, operating under the brands of major airlines. The correct answer indicates that Republic Airways operates for American Airlines, Delta Air Lines, and United Airlines. This partnership allows Republic Airways to provide regional service that connects smaller markets to major hubs, effectively increasing the reach of these larger airlines.

The collaboration entails operating flights using the major airlines' branding and scheduling while adhering to their operational standards. This is a common strategy among regional carriers, as it benefits both the regional airline in terms of passenger volume and the major airlines in terms of network expansion and customer convenience.