The Airstrip Explorer seems broken today (I did not check in a month or so, however). Many uncharted airstrips are shown, but many do not get a pushpin or marker (not sure what determines which work). Therefore, it's impossible to update them. If I search by any means (inside explorer itself, or in main site right side search entry field), it all goes to the URL like "http://www.shortfield.com/sfx/index.php?sno=14605.21*A", which in turn brings up the correct location on the map, but no information pop-in. Specifically, this works as intended for Big Bar (pushpin present), but not for Estancia (no push-pin).

Update: There is a workaround. Go into search on the main page and fetch the result. Right-click on the result and extract the ID. In case of Estancia it's 14605.21*A. Now, insert this ID into this URL:
http://www.shortfield.com/sfx/sf_airstr ... *A&tbl=faa
This will bring back the missing popup and allow for updates.

Update 2014/05/03: Looks like it works now.