AirNav provides free detailed aeronautical information on airports and other information to assist pilots in gathering information for flight planning. It's also useful for some hangar flying on those days when the weather or the checkbook keep you on the ground. Airport details include airport location, runway information, radio navigation aids and communication frequencies, FBO information, fuel prices, and a wealth of other information for pilots. Also tools for airport search, fuel price search, and a fuel stop planner. All searchable, all free.