I found an informative article from The Independent Traveler that looks at the extra fees charged for airline seats.

"Airline Perks Worth Paying For

June 23, 2011

The Truth About For-Fee Seating and Priority Boarding

Are airline priority boarding and preferred seating programs really worth our cash? We dissect a handful of offerings from the major airlines and reveal which programs can get you a great seat for a small price, and which should be avoided like the airplane cold.

Shy ~