FoxAlpha
Mother site of Helimage, air photography portal
France - english speaking - 4 websites

Picavia
Sister site of Helimage, dedicated to airliners
France - english speaking

Airliners
An incredible database of commercial and military planes pictures.
Sweden - english speaking - digital library

Eurocopter
France & Germany - english speaking - digital library

Sikorsky
USA - english speaking - digital library

Boeing
USA - english speaking - digital library

MD Helicopters
Netherlands - english speaking - digital library

Aviation-fr.info - L'encyclopédie de l'aviation
France - french speaking - more than 250 pages

Helimat
L'actualité hélico française
France - french speaking

Eurocopter Spotter Page
France - french speaking

HeliRegistre
Le registre des hélicos français
France - french speaking

Pégase
Franck Cabrol's website for warbirds and modern military planes enthousiasts.
Wallpapers - french & english speaking, more than 2 000 pics

Wingshots - aerial photography
Antoine Grondeau's website with aircraft walkarounds and photographs picturing all sorts of flying machines.
France - english speaking - more than 5 000 pics