Great freeware airports:

Pleurtuit - St. Malo
lfrdv1a.zip and Flightsim, lfrd2004-v1a.zip on Avsim

A truly amazing piece of photo-scenery.
This is the freeware work of the designer of the famous FlightScenery payware addons - and the same quality exists here.
The scenery manages to be both fully detailed and chuck-full of beautiful VFR landmarks AND frame-rate friendly!
You do not want to miss this one.

Photos by the creator.




Louisiana Wetlands
lawetlandsvol1.zip, lawetlandsvol1sr1.zip, louisianawetlandsv2.zip on Avsim

A beautiful set of small bush airstrips in southern Louisiana. These are all very close in proximity and are very well done, with custom AI traffic and plenty of animated birds.
Beware, these do not play nice with Ultimate Terrain, USA! As the readme says:
These FS Airfields are based on real-world private airfields that no longer exist due to coastal erosion and years of neglect and hurricanes...
so you may need to do some fiddling with scenery design techniques to use these with Ultimate Terrain. That's what I did, and have not regretted it!

Photos by the creator.