Assertion: helicopter | /r/HasProperty | expensive to operate
Facets:
value: compared to other forms of aircraft
type: OTHER
Source sentences:
text: They are noisy, relatively slow and more expensive to operate, compared to other forms of aircraft.
text: Unfortunately, this versatility comes at a price: helicopters with spinning rotors are mechanically more complex than planes with static wings, more prone to failure, need more maintenance, and are expensive to operate.