The sixth case is a Camp Hill woman who visited the NSW town of Kyogle, where four cases have emerged this week.
Premier Annastacia Palaszczuk says the new cases, which emerged after 14,216 tests, have been linked to existing infections with no mystery cases in the community.
She urged people to get tested, wear face masks and get vaccinated if they have not already done so.
"We want to make sure that this is not seeding into the community - so if you have any symptoms whatsoever come and get tested," she said.
"That's why the next 24-48 hours is going to be very critical to see if there is any seeding."
Chief Health Officer Jeannette Young believes the cases in the aviation cluster were probably picked up at an event on 20 September.
The Camp Hill woman's case has not clustered with any others - something Dr Young said made sense.
A Queenslander who flew home from Melbourne on 27 September has also tested positive, but has been in hotel quarantine and poses no risk.
So far, there have not been any new cases linked to the truck driver who stayed at two hotels at Spring Hill, and a hostel at South Brisbane.
Under stage two restrictions there are capacity limits for indoor venues and visitors to private homes are capped at 30 people.
Venues including cafes, restaurants, cinemas and theatres must only have one person per four square metres, while weddings and funerals are capped at 100 people.
Crowds at large venues will be capped at 75 per cent, with some fans set to miss out on the Rugby Championship on Saturday night and NRL grand final in Brisbane on Sunday.
Ms Palaszczuk denied Sunday's NRL grand final in Brisbane was having any influence on her decision over whether or not to lock down the southeast of the state.
"Absolutely none. Let me make it very clear that the health of Queenslanders comes first," she said.
Ms Palaszczuk said the current restrictions were adequate, but she will not hesitate to order the southeast into full lockdown if she is advised to.
"We're actually moving to tighter restrictions, our vaccination rates are up, people are checking in, but as soon as we see further seeding which is not from people who are in isolation, then they will be the trigger points," the premier said.