Air Lines, Airlines or Airways?
Terry Baker and Ken Pickford of the NetLetter team share a passion for the English language and the use of proper grammar. With all due respect to both gentlemen, I would like mention (with humour intended) that we should keep one important fact in mind. This is English!
The actual origins of the language seem to be a continuing subject of debate but we may say that it has been spread all over the globe and evolved differently depending on the region. Spelling and pronunciation may vary slightly between regions but slang almost creates a new unique language even within a single country.
Today’s technology has turned corporation names into verbs (Google it) and acronyms into nouns (RAM, LASER, RADAR, MODEM etc.). However, I think that one of the most fascinating aspects of language is the constant addition of compound words derived from the formation of new industries. 
This brings me to the phrase “Air Line” from which the noun “Airline” was derived. In the early days of the industry, “Air Line(s)” would have been used to distinguish this form of transportation from a “Cruise Line” or “Rail(way/road) Line” and referred to the actual routes. Trans-Canada Air Lines and Canadian Pacific Air Lines were named before the word “Airline” became part of the language. Since the addition of “Airways” , the three terms have been interchanged liberally; to the annoyance of many.
“Airline” is defined as “an organization providing a regular public service of air transportation on one or more routes”, in one quick Google search. If you have a week or two on your hands with absolutely nothing else to do, I suggest that you do a Google search for “Air Lines, Airlines or Airways” and settle in. Or, check out www.airliners.net for a condensed version of the debate.