In 2008, many airlines began charging for checked baggage and placed the blame for the new fee on high jet fuel costs. Last year (Q1-Q3 only), those checked bag fees added up to $2.5 million. Since 2008, airlines have collected almost $18 billion in checked bag fees.
But how much does it actually cost an airline in jet fuel to transport your suitcase? About $2 and maybe less...
http://www.freep.com/article/20140202/COL21/302020020
If only the writer'd made a better attempt at calculating the infrastructure and labor costs and factored those in as well...