Hawk Lead-In Fighter and F-35 Joint Strike Fighter jets based at Williamtown RAAF Base flew overhead as hundreds of people streamed through the aviation museum to look at the many restored and replica aircraft on display as part of a free open day to mark the double celebration.

"It's terrific to be able to celebrate with the Air Force because we are so closely associated with them. We operate on Defence property," Fighter World manager Bernie Nebenfuhr said.

"We have a great relationship with them and continue to be their most prominent community engagement arm. From here the public can view the contemporary jets that launch and return from the base as well as many of the aircraft that the Air Force operated in yesteryear."

Early on Monday, special guests were invited to Fighter World for a cake-cutting ceremony to mark the 80^th anniversary of the RAAF base, which opened in February 1941.

It is the first of two anniversaries that the RAAF is marking this year. The other is the 100-year anniversary of the Royal Australian Air Force in March.

Event guests and air enthusiasts were also treated to a flyover from a P40 Kittyhawk.

The aircraft was loaned to Fighter World for the day, which was displayed out the front of the museum next to the Raymond Terrace Sabre Jet, from Pay's Group based in Scone.

The Kittyhawk is significant to Williamtown. RAAF Squadron 450, the 'Fighter Bomber Squadron' that flew Kittyhawks during WWII, helped build the Williamtown base.

A large Squadron 450 display was set up inside Fighter World on Monday, alongside RAAF information, the history of the Williamtown base and the regular museum exhibits.

The doors the museum opened free to the public from 11am, and was immediately inundated with people. The open day was held to mark the 30^th anniversary since Fighter World opened in its current location in February 1991.

"Busy but really wonderful" is how Mr Nebenfuhr described the open day which was also attended by past servicemen and women who have flown the aircraft on display and former Fighter World committee members and volunteers who remarked that they "like what they're seeing in terms of progress and development of the centre".

Fighter World's volunteers, past and present, were recognised in a service about noon on Monday, punctuated by a second cake-cutting.

"Our volunteer workforce is our backbone. We really wouldn't exist without them," Mr Nebenfuhr said. "They devote endless hours week in, week out to keep the place going, to help prepare some of the exhibits, rebuild aircraft to sometimes build replicas from scratch."

Les Bowden and Neville Masters have been volunteering at Fighter World for 25 years. Both joined in 1995.

"I've enjoyed, and continue to enjoy, my years here. There's a lot of camaraderie that goes on," Mr Bowden said. "This place when I first came here was fairly bare. But they've gained more aircraft and exhibits over the years. It's grown to the point where we don't have any room to put anything."

Mr Bowden remembers travelling to Nowra with former Fighter World manager Bruce McConnell to secure a CA-25 Winjeel for the museum.

"It was meant to be any easy job," he recounted. "Just take the wings off and put it on a truck. Bruce said there would only be two bolts on either wing so they'd easy to come off.

"We get down there and there's 48 bolts on the bottom of each wing and 48 bolts on the top of each wing. We finally got them off.

"Then when we went to put it on the truck the next day - no cranes or anything like we have today - the undercarriage was too wide for the truck. There was a big square of flooring that we used to transport it."

Mr Bowden and a group of Fighter World volunteers are now working on building a replica of a Spitfire for exhibit.

To mark the RAAF's 100^th anniversary, Williamtown RAAF Base will host a number of events including a commemorative service at Nelson Bay and a reception on the base on the centenary date, March 31.

In celebration of Williamtown's birthday in August, there will be RAAF flying display over Port Stephens and a heritage culture display at Fighter World.

The RAAF Base celebration was hosted by Deputy Air Commander Australia, Air Commodore Benjamin Sleeman.

"RAAF Station Williamtown officially opened in 1941 with just three officers and 96 airmen, and was established to provide protection for the strategic port of Newcastle and steel manufacturing facilities of the Hunter region," he said.

"Initially served by four runways, the base was home to the Williamtown Flying School. Today, Williamtown is the largest fast-jet base providing critical support to Air Force's air power capability for Australia."

SADFO Group Captain Anthony Stainton was proud to be part of the 80 h celebrations, including the ceremonial cake cutting with an Air Force junior member and indigenous man, Leading Aircraftman Dallas Fisher.

"I am honoured to start my first year as the Senior Australian Defence Force Officer at this base during a year full of milestones," Group Captain Stainton said.

"Having served at Williamtown previously, I have seen the incredible changes around the base over recent years and to be celebrating eight decades of operational service in Air Force's centenary year makes it even more significant."

Throughout WWII, a number of Empire Air Training Scheme squadrons formed at Williamtown before proceeding overseas in October 1942. Following the war, RAAF Base Williamtown began its new life as the Air Force's main fighter base, including squadrons of Gloster Meteor and F-86 Sabre fighter aircraft.

Upgraded to a tactical fighter base in 1983, RAAF Base Williamtown is now home to Air Combat and Surveillance and Response Groups, including the F-35A Lightning II and E-7A Wedgetail aircraft, with more than 3700 military and civilian personnel working on the base, supported by around 500 contractors.