Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Mackay to Rio de Janeiro as you normally would.
For a flight from Mackay to Rio de Janeiro, you will be flying from Mackay. Mackay (MKY) is just 3.3 km from the centre of the city. Mackay is the only Mackay airport and it handles 0 outbound flights to Rio de Janeiro per day. 0 airlines have flights to Rio de Janeiro from Mackay on a regular basis.