What is a good definition for the term "Airline"?

The term is used extensively, and it's meaning is well understood at the one end of the spectrum: air carriers flying passengers on large aircraft on scheduled routes. However, the other end of the spectrum seems to be far less defined or understood. This question is a good case in point: Why don't we have helicopter airlines?

I am primarily interested in exploring the term from an operational standpoint, not a entitative standpoint, but both are valid.

I am familiar with the FAA's 14 CFR 1.1 definitions of Air Carrier and Commercial Operator, but I am not aware of any FAA provided definition of Airline. I am asking this definition from my background of knowledge of FAA regulations. However, I would be interested in an answer that would be valid worldwide.

Criteria to consider include the following, all of which apply to Air Carrier operations (some of these criteria overlap):

  1. A Single pilot company, vs a multiple pilot company

  2. Passenger carriage vs freight

  3. Scheduled vs on-demand

  4. §135, vs §125, vs §121, etc.

  5. Aircraft category— fixed wing vs rotorcraft

  6. Aircraft size— number of passenger seats, pounds of cargo payload

  7. Common carriage vs non-common carriage or contract carriage

  • $\begingroup$ Are you wanting the legal definition, or a colloquial one? $\endgroup$
    – Ron Beyer
    Oct 17, 2016 at 14:44
  • $\begingroup$ @RonBeyer Is there a legal definition, and if so, what is its applicability? The operator, the operation, the Airline Deregulation Act of 1978? $\endgroup$
    – J W
    Oct 17, 2016 at 14:53
  • 1
    $\begingroup$ The common definition for me: An airline is, by metonymy, a company that operates airlines, the latter airline being the infrastructure and people in place to support the operations: ticket sales, aircraft, airfields, ground operations, maintenance, crews. At the beginning of airlines it also included the navigation aids (radio, lighting) and rescue. American airlines would be a reference to the company operating routes in Americas. It's to compare with railways (e.g. Zambia Railways). $\endgroup$
    – mins
    Oct 17, 2016 at 17:18
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    $\begingroup$ @mins I would say the word "airline", as is much of aviation terminology, is borrowed directly from nautical terminology. Ocean travel companies were called "lines" long before air travel was invented. I don't think the word was ever understood to mean the infrastructure. The motonymy occurred in the previous industries. That borrowing from sea travel, as George Carlin pointed out, resulted in English speakers saying they're getting on a plane. Whereas I would much prefer to be in the plane. $\endgroup$
    – TomMcW
    Oct 18, 2016 at 5:46
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    $\begingroup$ Manx2, bits.blogs.nytimes.com/2014/02/07/… seems relevant... $\endgroup$
    – DJohnM
    Oct 18, 2016 at 19:50

2 Answers 2


According to ICAO atleast, airline refers only to international operations. From the Convention on International civil Aviation:

For the purpose of this Convention the expression:

a) "Air service" means any scheduled air service performed by aircraft for the public transport of passengers, mail or cargo.

b) "International air service" means an air service which passes through the air space over the territory of more than one State.

c) "Airline" means any air transport enterprise offering or operating an international air service.

So, the correct term for common usage (atleast according to ICAO) is 'air service'. Note that ICAO is more concerned with international operations. However, even the FAA definition is more or less on these lines (though it doesn't say anything about 'airline').

Air Carrier — a person who undertakes directly by lease, or other arrangement, to engage in air transportation. This includes an individual, firm, partnership, corporation, company, association, joint-stock association, governmental entity, and a trustee, receiver, assignee, or similar representative of such entities.

The dictionary definition however, looks more apt for the common usage:

An organization providing a regular public service of air transport on one or more routes.

  • 3
    $\begingroup$ ICAO's "international" definition is not helpful to this discussion since their explicit purpose is to organize international operations, which is does not encompass the scope of this question. $\endgroup$
    – J W
    Oct 17, 2016 at 15:10

Just a suggestion:

"A company that generates revenue by transporting people or cargo by aircraft."

  • 2
    $\begingroup$ I don't think revenue even needs to be in there, but scheduled/semi-scheduled fixed routes do. The dictionary definition of "an organization providing a regular public service of air transport on one or more routes." seems correct. Charter airlines (without fixed routes) are a thing, but are a specific subset of a simple "airline" $\endgroup$
    – Jon Story
    Oct 17, 2016 at 15:02
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    $\begingroup$ This can be a good starting point, but it's slightly ambiguous. Would air taxi or charter flights (Part 135 under the FAA) count under this definition? What about aerial tours? $\endgroup$
    – Cody P
    Oct 17, 2016 at 16:18

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