For whatever reason "how do I download X aircraft from Git" seems to be a pretty popular question around here, so I figured why not write a guide:
1. Go to http://mapserver.flightgear.org/git/?p=fgdata;a=tree;f=Aircraft.
2. Navigate into the directory of the aircraft you want to download.
3. Just below the top navigation bar, click the big beautiful link labelled "snapshot."
4. Extract and enjoy!