The following question refers to the third article in the packet, "America's Flyers Can't Expect both Cheaper Fares and more Legroom." The following quote alludes to which source of low costs? "Most of those costs are fixed, pretty much. So the best way to make healthy profits is through airfare. In order to keep fares low, airlines need to pack as many people onto the planes as they can." Group of answer choices Learning curves "Policy" Economies of scale