CURRENT AIRFIELD / AIRPORT DATA SOURCES

You can use the Internet to check on an airfield to see if it is active.  There are several sources.  AirNav is the best, in my opinion, and contains a large amount of data about airfields.  GCR company provides what is referred to as the "5010" list.  This is a listing of airfields from the FAA's data base (the FAA's website has a link to it for you too). Another site is World Aeronautical Database but is more difficult to use since it was revamped.  The AOPA offers an online service, but you have to subscribe to it.  All of the others are open free access.

You can buy the current products available from the NOAA/FAA - directories, charts, etc. on the Internet or your local aviation supply store(s).