Hello!
At the Essen fair in Germany, the Balloon Busters expansion kit has been presented:
The box includes a ballooon and a Nieuport 16 with rockets, plus special rules and counters to play with them. You need a basic set to play, anyway.
There will be two different color schemes: brown balloon and yellow one, with two different Nieuports (one is from Lafayette Escadrille).
Here a video with some details:
http://richardbliss.typepad.com/