But the airport has hit back at criticism of its expansion plans saying the affected homeowners "should have known" their houses were under a flight path when they were built or purchased.

The airport's proposal to greatly expand freight operations is a major piece of its draft master plan released earlier this week.

The draft plan outlines the airport's vision for the next 20-year period and also includes the potential construction of a second, parallel runway.

As part of those plans, the airport notes that 624 homes in Jerrabomberra currently under the flight path will see an increase in air traffic volume and related air traffic noise over the coming years.

The plan also stipulates that: "The frequency of aircraft movements and the size of the aircraft are forecast to increase indefinitely into the future."

But Stephen Byron, managing director of the Canberra Airport, expressed little sympathy for those residents affected in comments to The Queanbeyan Age yesterday.

"Most of the 624 homes have been built [or] purchased since 1995," Mr Byron said. "The households would/should have known the houses were under the flight path.

"The NSW Government recognises it is inappropriate to have residential development with ANEF 20. So the fact is those 624 houses are located in an area that has been repeatedly deemed unacceptable for residential dwelling in relation to potential aircraft noise."

In essence, ANEF or Australian Noise Exposure Forecast, is a measure of total aircraft noise exposure in a particular area.

The system is used to restrict developments around airports where aircraft noise could be of concern to residents. The ANEF system is also designed to protect airports from residential developments in surrounding areas from curtailing airport operations.

In 1995, the Federal Government also introduced Noise Abatement Areas over much of Canberra and Queanbeyan, restricting flight movements into and out of Canberra Airport

Parts of Jerrabomberra and Tralee however, lie outside those areas and inside the ANEF 20 zone, giving those homeowners little recourse to fight the airport's plans.

But Jerrabomberra Residents Association president Michael Ziebell said the group remained opposed to the freight hub idea.

And he said the notion of jet aircraft flying over Jerrabomberra at all hours of the day and night was "just not on".

"We're definitely opposed to it," he said. "We don't want half a dozen 747s coming in overhead on a still Canberra night.

"One or two a night might not be noticeable but if they've already got them coming in, how many is it going to be in three or four years?

"We'd rather see it knocked on the head now rather than getting to that stage."