Mainline (aeronautics)

Delta Air Lines is an example of a mainline airline

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.

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 USA, examples of mainline passenger airline flights include those operated by American Airlines, Delta Air Lines, and United Airlines but it would not include flights operated by regional airlines American Eagle Airlines or Comair with Regional jets or the services of mainline "non-airline" regional airline marketing brands such as AmericanConnection, Delta Connection, or United 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 the Delta Shuttle, or the mainline United's Ted, and 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.

All of the - mainline legacy - airlines listed below operate international, intercontinental, or transoceanic airline services using jet airliners. Additionally, all the - mainline legacy - carriers listed happen to be within the group of United States airline carriers known to statistically be major carriers.

All of the following legacy airlines and their holding companies operate using secondary regional carriers via airline marketing sub-brands commonly marketed as "Express" or "Connection" services.

All of the following airlines in some form operate in association with a regional component. All legacy carriers are among the group of US airlines known as "mainline" carriers.

Major U.S. Mainline Carriers

Mainline Legacy Carriers	Non-Mainline but "owned" Regional Affiliate Carriers	Non-Mainline Regional Brands
American Airlines	(MQ) American Eagle Airlines (OW) Executive Airlines	AmericanConnection ( MQ) d/b/a American Eagle (OW) d/b/a American Eagle
Continental Airlines	No regional affiliates	Continental Connection Continental Express
Delta Air Lines	Comair	Delta Connection
United Airlines	No regional affiliates	United Express
"Non-Legacy Carriers" using "mainline" equipment
Alaska Airlines	Horizon Air	Alaska Horizon Alaska SkyWest
Frontier Airlines	No regional affiliates	"Frontier Airlines operated by Lynx Aviation" "Frontier Airlines operated by Republic Airlines"
JetBlue Airways*	No regional affiliates	No regional brands
US Airways	PSA Airlines Piedmont Airlines	US Airways Express
Airlines using "mainline" equipment minus any regional components
AirTran Airways*	No regional affiliates	No regional brands
Allegiant Airlines*	No regional affiliates	No regional brands
Hawaiian Airlines**	No regional affiliates	No regional brands
North American Airlines***	No regional affiliates	No regional brands
Omni Air International	No regional affiliates	No regional brands
Ryan International Airlines*	No regional affiliates	No regional brands
Spirit Airlines*	No regional affiliates	No regional brands
Southwest Airlines*	No regional affiliates	No regional brands
USA3000 Airlines*	No regional affiliates	No regional brands
USA Jet Airlines*	No regional affiliates	No regional brands
Vision Airlines	No regional affiliates	No regional brands
World Airways*	No regional affiliates	No regional brands

Notes:
(*) These airlines operate mainline equipment but do not wholly "own" regional airlines or have "non-owned" regional affiliates.
(**) Hawaiian Airlines does operate transoceanic international and intercontinental ETOPS services but does not have a regional component
(***) North American Airlines does operate transoceanic international and intercontinental ETOPS services as a supplemental / charter airline carrier, but does not have a regional component

References

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