Just thought this was pretty cool. Not a download, just online. Aviation Charts on Google Maps | iFlightPlanner
download the 3d overlay for google earth: http://www.3dairspace.org.uk/airspace.html- A better overview than I can give here. 3D Airspace Map Inside Google Earth! Plus... FAA Sectional geoTIFFs FREE - Professional Land Systems | Knoxville Land Surveyors
download the 3d overlay for google earth: http://www.3dairspace.org.uk/airspace.html- A better overview than I can give here. 3D Airspace Map Inside Google Earth! Plus... FAA Sectional geoTIFFs FREE - Professional Land Systems | Knoxville Land Surveyors