Another fun example is the Louisville International Airport which was originally named Standiford Field, thus the airport code SDF and even locals still sometimes refer to it as Standiford, but in this case was renamed to the more obvious choice (Louisville International Airport) to confuse people less.

A further tangent, but the more obvious airport code LOU is still in active use across town at Bowman Field, the city's original air field (definitely not an airport) and these days the oldest remaining continually operating air field in the country.