Mainline (aeronautics)

A mainline flight by an American Airlines Boeing 777-223ER lands at London Heathrow Airport, England

Unlike many other airlines, JetBlue's mainline equipment includes both the Emb-190 and A320. Flight attendant aircrew members are trained to operate on both types of equipment, while at the traditional legacy carriers, such operations on the smaller aircraft are mostly outsourced to smaller, usually independently owned regional airlines.

Embraer E-190. Similarly to JetBlue, US Airways and Air Canada both operate the Embraer 190 as part of their mainline fleets.

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 now defunct 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.

Often US mainline airline carriers operate in-house brands such as United p.s. to cater to business segments such as the short-range air shuttle, low-cost, or premium-service flights which normally would not support the traffic or revenue yield needed for the traditional operation of larger mainline aircraft with over 100 passenger seats between selected city pairs.

Major U.S. Mainline Carriers

Airline	Regional subsidiaries^1	Regional brand^2
Legacy carriers
American Airlines	Envoy Air PSA Airlines Piedmont Airlines	American Eagle
Delta Air Lines	Endeavor Air	Delta Connection
United Airlines	No regional subsidiary	United Express
Alaska Airlines	Horizon Air	Alaska Horizon Alaska SkyWest
Hawaiian Airlines	No regional subsidiary	Ohana by Hawaiian
Low-cost carriers
Allegiant Airlines	No regional subsidiary	No regional brand
Frontier Airlines	No regional subsidiary	Great Lakes Aviation^3
JetBlue Airways	No regional subsidiary	Cape Air^3
Southwest Airlines	No regional subsidiary	No regional brand
Spirit Airlines	No regional subsidiary	No regional brand
Sun Country Airlines	No regional subsidiary	No regional brand
Virgin America	No regional subsidiary	No regional brand

Notes:
¹ Wholly owned subsidiaries with separate operating certificates flying regional jets under the regional branding.
² Branding used for regional feeder service and commuter flights. Operated either by a regional subsidiary or under contract by an independent regional airline.
³ These independent airlines operate regional aircraft under codeshare agreements with a mainline carrier.

See also

Flag Carrier

References

• , AA and early references to mainline, regional and B-scale