Jetstar started to Hamilton Island, and then all the rich people who live on Hamilton Island complained that people flying there on low fares were lowering the tone of the island, and the Jetstar planes were not comfy enough for rich people. So Qantas had to restore one of their own flights so that people could have business class seats and a free biscuit and a coffee. If you go to the Qantas site that will show you which schedules are operated by Qantas and which by Jetstar.