What is the population of a city where Rockhampton Airport has direct flights to 
Rockhampton Airport: Rockhampton Airport ("Connor Park") (IATA: ROK, ICAO: YBRK) is a major Australian regional airport in West Rockhampton that services the city of Rockhampton, with direct flights to the cities of Brisbane, Townsville, Gold Coast and Mackay. Brisbane:  Brisbane's metropolitan area has a population of 2.4 million, and the South East Queensland region, centred on Brisbane, encompasses a population of more than 3.5 million.
2.4 million