The British Airways (BA) flight from Geneva, with 132 passengers and five crew on board, was hit by what is believed to have been a drone as the plane approached the London Heathrow Airport at 12:50 BST on Sunday.
A police investigation is under way following the incident. BA said it would give the police "every assistance with their investigation". No arrests have been made, police say.
After safely landing the plane, the pilot reported an object - believed to have been a drone - had struck the front of the Airbus A320.
BA said in a statement that the plane was inspected and cleared for the next flight.