The Dallas Morning News uses data, quotes Oliver Wyman's Vikram Krishnan on airline capacity

Airlines in most regions of the world have been adding capacity without adding airplanes. data show that in the last decade the number of seats and size of planes have increased. Since 2009, the number of seats per airplane for the world rose 13.5 percent.

A Dallas Morning News chart uses data to show the increase. The daily newspaper quotes Oliver Wyman Partner Vikram Krishnan: “Upgauging to larger aircraft is the trend du jour. Network carriers are switching some regional jet operations to larger jets with multiple cabins, since these are cheaper to operate per seat, primarily because of fuel costs. Southwest Airlines is adding the larger 737-800 to its fleet, which has 32 more seats than the airline’s typical plane. Watch for this trend to stabilize or even reverse if fuel prices decline.”