However, other factors, such as difficulties regarding refinery capacity, may cause unusual divergence in the trends of crude oil and jet fuel.
Often, contracts for portions of an airline's jet fuel needs will overlap, with different levels of hedging expiring over time.
[citation needed] During the 2009-2010 period, the studies for the airline industry have shown the average hedging ratio to be 64%.
Southwest Airlines has tended to hedge a greater portion of its fuel needs as compared to other major U.S. domestic carriers.
Between 1999 and 2008, Southwest saved more than $4 billion through fuel hedging under the strategic leadership of former CFO Kelly (who became CEO in 2004, and President and Chairman in 2008).