The suit, which seeks unspecified monetary damages, also alleges that the helicopter was designed and built by Airbus Helicopters, a unit of Airbus, with flaws to its tail rotor system which malfunctioned and made the aircraft "uncontrollable in the event of a failure, especially at low speeds, hover and/or liftoff."
What is the relationship between 'Airbus' and 'aircraft' in the context of the input sentence.
Options: chief executive officer, product/material produced, developer, owned by