Just expanding on one of the points made by Scroggs. There are fundamentals in the business models of airlines which make them inherently inflexible and slow to be able to respond to market forces. This is driven largely by their fixed cost bases. To take one example many carriers lease aircraft as opposed to owning them. When loads/yields drop as a result of factors outside of the control of an airline such as 9/11 the airlines cannot simply return an aircraft to the lessor and say sorry we can’t pay you anymore as this will trigger a host of penalty clauses in the lease agreement. So with a drop in turnover through lower bums on seats the only way to try to keep profitability in check is to find other costs to cut. Hence pilots, cabin crew and other staff are often the easiest targets and thus you get your cyclical pattern evolving.