From their website:
Fantasy Flight Games is pleased to announce the upcoming release of Flight of the Giants, an exciting expansion for Wings of War.
Flight of the Giants is the first expansion set for Wings of War, introducing into the game early bomber planes, with new rules to handle their extended crews and fighting capabilities. You can now maneuver a huge Zeppelin Staaken, a Friedrichshafen G.III, or a Handley Page O/400, avoiding the fire of enemy fighters and searching for your target.
Flight of the Giants features 8 different bombers of the Allies and the Central Powers, such as the Felixstowe F.2A, Zeppelin Staaken R.VI, and Caproni Ca.4.