A low-cost carrier or low-cost airline (occasionally referred to as no-frills, budget or discount carrier, and abbreviated as LCC) is an airline that is operated with an especially high emphasis on minimizing operating costs and without some of the traditional services and amenities provided in the fare, resulting in lower fares and fewer comforts. To make up for revenue lost in decreased ticket prices, the airline may charge extra fees – such as for carry-on baggage. As of October 2019, the world's largest low-cost carrier is Southwest Airlines, which operates in the United States and some surrounding areas. The term originated within the airline industry referring to airlines with a lower operating cost structure than their competitors. While the term is often applied to any carrier with low ticket prices and limited services, regardless of their operating models, low-cost carriers should not be confused with regional airlines that operate short flights without service, or with full-service airlines offering some reduced fares. Some airlines actively advertise themselves as low-cost, budget, or discount airlines while maintaining products usually associated with traditional mainline carrier's services—which can increase operational complexity. These products include preferred or assigned seating, catering other items rather than basic beverages, differentiated premium cabins, satellite or ground-based Wi-Fi internet, and in-flight audio and video entertainment. More recently, the term "ultra low-cost carrier" differentiates some low-cost carriers, particularly in North America where traditional airlines increasingly offer a similar service model to low-cost carriers.