The purple hang gliders are defects in the imaging sensor. It's normal to have a hot pixel or two on a camera sensor -- on all but the most expensive digital cameras. Your computer screen probably has a bad pixel or two as well. Not something to worry about. But seeing a large group of these defective pixels is bad news. My PV2 has them too, and that's why I'm sending it back. The sensors, evidently, are not being thoroughly tested before being assembled into cameras. The testing adds cost and time -- and I'm sure Colin was a a big rush to get the PV2 out in time for christmas -- warts and all.
This camera is marketed as a 14 megapixel camera -- and it's no where near that. While the imaging sensor may be recording that much data, the JPG compression algorithm is far too agressive, and, as far as I know, not user controllable. This may well have been a design choice because it facilitates downloading and sharing images while the PV2 is still in flight -- a cool feature no doubt, but if the goal is for high quality 14mpx images, rather than fast download times, the compression isn't appropriate.
Unlike the defective image sensors, the jpg compression can be likely fixed with a software upgrade. And the problem will go away entirely once the RAW file update happens. However, DJI's web site says the camera will shoot RAW. But as well documented in other threads here, the RAW files are useless with the current state of the software.
My advice to all new P2V owners -- check for purple hang gliders, and watch for the expiration of your return policy from where you purchased. And for new purchasers -- know that a flood of P2Vs are being returned to the vendors. Make sure you get one that is factory sealed. And even then, test it thoroughly. Better yet, wait until RAW is truly supported. RAW is in beta -- and Russell Brown -- Senior creative director at Adobe -- is getting amazing results with the new RAW files.