2. How do you understand the term “code-sharing”?

Code sharing is a business term which was first originated in the airline industry in 1990 when the Australian airline, Qantas Airways and the US's American Airlines combined services between an array of US domestic cities and Australian cities. The code share was part of a "cooperative services" agreement between the two carriers before the various airline alliances were formed. Code sharing is a commercial agreement between two airlines that allows passengers to use a ticket from one airline to travel on another. Most major airlines today have code sharing partnerships with other airlines, and code sharing is a key feature of the major airline alliances. Lots of airlines, including all the big legacy lines, are involved with codesharing arrangements. Those arrangements permit you to buy through tickets on routs that no single airline can serve. They may also provide opportunities to cut the cost of your airfare.