The Bureau of Transportation created statistics analyzing the airline fees of the first nine months in 2012, found out that consumers are willing to spend more than $6 billion in baggage, cancellation and admin fees. Fees annoy customers because the true cost of flying is not shown on their ticket and they have no choice but pay for those fees. Yet, the "true cost of flying" is not something that can be easily measured. In all sense, additional fees are reasonable and defensible to accommodate various passengers. Airlines with increasing ticket price is trying to take advantage of desperate flyers, especially business travelers who can expense their ticket cost to their company.
Source: http://www.businessinsider.com/americans-spend-6-billion-airline-fees-2013-1