Official Sites
FlightGear Official Hangar: http://www.flightgear.org/Downloads/aircraft-2.0.0/
FlightGear CVS Hangar: OBSOLETE - moving to Git version
FlightGear Liveries: http://liveries.flightgear.org/
FlightGear Forums: http://www.flightgear.org/forums/
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The rest...
FGUK Webcentre: http://www.fguk.eu
Liam's hangar (FlightGear Airliner Resources): http://flightgearliveries.ning.com/
Emmanuel Baranger's Hangar: http://helijah.free.fr/flightgear/hangaren.htm
MOJO's Hangar: http://mojos-hangar.webs.com/
United Free World: http://www.unitedfreeworld.com/
DFaber's Hangar: http://www.sol2500.net/flightgear/aircraft.html
Hoerbird Hangar: http://www.hoerbird.net/aircrafts.html
Buckaroo's Hangar: http://ltts.crlt.indiana.edu/grn/flightgear/
Tat's Hangar: http://macflightgear.sourceforge.net/home/aircraft
JCHND's Hangar: http://jchnd.blogspot.com/
Prestes' Hangar: http://presteshangar.wikidot.com/start
Armchair Ace Liveries: http://aaliveries.yolasite.com/
Charles Ingels Hangar: http://charles.ingels.free.fr/flightgear/
Dodger4's Livery hangar: http://dliveryhangar.synthasite.com/
Simbabeat's Hangar: http://simbabeathangar.webs.com/
NicQ's Workshop: http://sites.google.com/site/nicqsworkshop/
Nick's Flightgear Hangar: http://nickfg.blogspot.com/
San Francisco Pilots Official Hangar: http://theomegahangar.webs.com/
Wingtipped's Hangar: http://www.wingtipped.webs.com/
Skyop's Hangar: http://skyopshangar.byethost17.com