What is the relationship between 'Airbus A380' and 'Singapore Airlines' in the context of the input sentence.
Options: subsidiary, creator, operator, original broadcaster

On the major airlines operating long-haul services out of Sydney and Melbourne, economy seat width ranges from 43 centimetres to the 48.25 centimetres on Singapore Airlines Boeing 777‑300ER, Airbus A380 and A330-300 flights.
operator