Smaller regional aircraft accommodating 50 passengers or less have been a staple in US aviation for decades. Given that the country has several regional markets outside of major cities, carriers such as SkyWest Airlines have a robust operation with contracts with all three legacy contenders: American Airlines, Delta Air Lines, and United Airlines. The most popular version of this aircraft is the Bombardier CRJ200, but others have been made, such as the Embraer ERJ series and the original variants of the De Havilland Dash 8 family. However, over the years, these small workhorses have become increasingly rare.