There are two recorded incidents of drones colliding with aircraft.
The one reported at the link in Canada, occurred in October.
The drone hit the plane’s wing but the aircraft sustained only minor damage and was able to land safely.
The second, in the US, involving a military helicopter, again landed safely but with damage to its main rotor blade.
Both these incidents support the focus on drone conflict risk as highlighted by a Navigatus airspace surveillance options study completed in 2015.