An Airline is a company that provides air transport services or air travel for people and cargo. Millions of people travel via flights every single day. Airlines use aircraft i.e. aeroplanes to provide travel services. Many times airlines form agreements with other airlines primarily for connecting flights i.e. connecting places. DELAG, Deutsche Luftschiffahrts-Aktiengesellschaft I was the world's first airline and it was founded on November 16, 1909, with government assistance, and operated airships manufactured by The Zeppelin Corporation. The headquarters were in Frankfurt.
Airlines come in different sizes based on their type. Generally domestic airlines are smaller in size compared to full-service international airlines which also include double-decker airlines. Thus, Airline services can be categorized as: intercontinental, domestic, regional, or internationall. The largest airline currently is American Airlines Group. The article World Major Airlines lists the famous Airlines in the world.

World Major Airlines listed in alphabetical order: