You don't need a source. An object striking an aircraft in flight is devastating, and can be very fatal. Just because the object was made in China vs. hatched out of an egg doesn't really matter... the results will be the same.
Well, according to wikipedia, only between 11-15% of bird strikes result in damage to the aircraft. Apparently large birds like geese are the main danger.
I imagine a similar distribution with drone strikes, as most drones do not weigh as much as a goose, at least of those in the hands of a typical idiot (who would fly in the path of a plane).
That's why 'very high fatality chance' doesn't seem right to me, but I can't find any statistics on it.
That's because there have not been any: https://en.wikipedia.org/wiki/List_of_unmanned_aerial_vehicl...