Global airline passenger miles in 2015 will increase 7 percent year over year, the largest increase in five years,

according to PricewaterhouseCoopers' annual airline industry report, released Monday. The firm attributed the increase to “steady economic growth, higher disposable incomes in emerging markets and increased air travel in developing economies.” PwC also noted that capacity is growing at an even faster pace due to lower fuel costs, so global load factors will decrease slightly this year and passenger yield will decline 2.5 percent.