"and pilot/observer was able to spot grey drone, 30cm in size, while travelling +300km/h ?"
As others have said, maybe the pilot was looking in just the right direction at the time and, being a pilot and interested in flying, maybe he owns a drone and is familiar with specific models, possibly even owning that particular model. Ever noticed how when you get a new car suddenly it seems as if everyone on the road bought the same model as you?
Biting the hand that feeds IT
