The Duke and Duchess of Cambridge's arrival was announced with the sound of the RAAF band, followed by the deafening roar of four F/A-18F Super Hornets from the No 6 Squadron flying in formation overhead.

After meeting dignitaries – including Queensland Premier Campbell Newman, Defence Force Chief David Hurley and Ipswich Mayor Paul Pisasale – on the red carpet, the royal couple inspected one of the Super Hornets and a flight simulator.

They then toured the RAAF Base Amberley memorial garden, in honour of defence personnel who had lost their lives.

While there, the Duchess of Cambridge was presented with a boomerang by 3½-year-old twins Ellijah and Tobee Dyer during the royal couple's tour of Amberley RAAF base on Saturday.

"It's for me?" Kate asked as she bent to receive the package that contained the small wooden gift.

"It's for George, from us," tiny Ellijah told her.

"Thank you very much," the Duchess replied.

The pint-sized prince will have to wait to receive the toy as he did not travel with his parents for the Queensland leg of their tour.

The Duke and Duchess planted a native eucalyptus shrub – the Plunkett Mallee – at the garden.

A plaque to mark the occasion read: "This Tree of Remembrance was planted by Their Royal Highnesses The Duke and Duchess of Cambridge in honour of the service and sacrifice freely given by the Men and Women of the Royal Australian Air Force."

The royal couple solemnly bowed their heads while a prayer was read out and four Super Hornet jets, once again, flew over in formation.

The royal couple chatted to onlookers before they were taken to meet Defence Force personnel and bereaved service family members at a special reception at the base's mess hall.

Warrant Officer Peter Gwyther was one of those who was able to speak briefly to the prince.

“He was pretty straight down to earth, wasn't stand-offish or anything. He was very approachable. It was a great honour,” he said.

Warrant Officer Gwyther said he was impressed with both William and Kate, who he thought would put to rest any future talk of an Australian republic.

“I think it will strengthen their foothold in Australia. I think most Australians are very proud to be a part of that royal culture,” he said.

General Hurley said the royal visit was a fillip for all defence personnel.

“In their day-to-day job, they probably don't think of the royal family a lot – you know, it's not something you think of every day,” he said.

“(William) will become in the future an honorary air commodore for the 1st Squadron here and we'll keep those links we've had.

“And for them, just to see someone you see on TV or read about in newspapers – to meet them in the flesh is just a thrill for everybody.”