A mainline flight is a flight operated by an airline's main operating unit, rather than by regional alliances, regional code-shares or regional subsidiaries. In the United States, examples of mainline passenger airline flights include those operated by American Airlines, Delta Air Lines, United Airlines, and US Airways but it would not include flights operated by regional airlines Envoy Air, Executive Airlines, Piedmont Airlines, or PSA Airlines with regional jets or the services of regional airline marketing brands such as American Eagle, Delta Connection, United Express, or US Airways Express  aboard lower-capacity narrowbody jets and turboprop aircraft, such as those produced by Embraer or Bombardier, that do not have transcontinental range.