If an airliner were to hit a drone and sustain "Minor cosmetic damage", the costs could be quite high.
Lets say it hit the leading edge of a wing.
The aircraft would require inspection to assess the damage. If it was a dent more than about 1mm deep or a scratch then NDT testing would be required to ensure there was no crack. This could take several hours, so loss of service for the airline.
If the dent was more significant then a leading edge change may be required taking a lot more time.
The cost in insurance terms could easily be $100,000 to $500,000.
If it involved an engine then we are talking several millions.
So when this happens, who is going to pay?