Spirit Airlines serves the United States, Latin America, and Caribbean as an airline operator. It primarily offers customers unbundled base fares to strip out any unneeded travel amenities. If needed, a customer can elect for additional options at an extra charge. Flight crews are entirely interchangeable across all aircraft, and maintenance and other support services are simplified due to not having an overly complex fleet. The company has one operating segment, air transportation, owing to its systemwide route structure. It may decide to expand its network if a market is underserved or overpriced. The majority of revenue is derived from the United States.