Qantas is gaining share from its main rival, Virgin Australia, new analysis shows, as low-cost subsidiary Jetstar takes delivery of bigger aircraft and adds cheaper seats to a softening domestic aviation market.

As Qantas prepares to unveil its full-year earnings on Thursday, Barrenjoey analyst Matt Ryan said Australian Competition and Consumer Commission data showed the group, including Jetstar, grew passenger numbers 6 per cent in the June quarter, ruling off its second-half passenger growth at 8 per cent.