Well, actually, it's a big mystery to me. Recently, Weekender stumbled across what at first seemed to be an oversized Nissen or Quonset hut (pictured) in the middle of nowhere.

You must know the old Nissen huts? These semi-cylindrical, corrugated iron buildings were a mainstay of the Australian military in World War II.

Now increasingly rare, some later ended up in Hunter Valley paddocks as storage units.

Others, from Belmont North to suburban Cessnock, housed post-war migrants or returned servicemen. Many are still used as accommodation.

But this 'shed' in Branxton was massive, of aircraft hangar proportions.

Could it have been a wartime relic leftover from an emergency WWII airstrip nearby?

Or perhaps, it had just been transplanted there sometime, to fill a new need such as hay or grain storage?

However, I was intrigued by the notion that this could have been the last reminder of an abandoned airstrip. A lot of them were once secretly created up and down the NSW coast in case of a Japanese invasion more than 75 years ago.

But no one seems to know for sure, with site use apparently having changed several times over the decades.

All I eventually discovered was that this 'hangar', not unlike the semi-circular building housing Fighter World at RAAF Williamtown (but much smaller), may have been brought to the land in the 1990s.

While this long, ageing 'hangar' seems to be of WWII vintage, there was once an office inside and gear is now stored there.

The high doorways at both ends today would suit forklifts, but not aircraft.

Maybe it was re-configured some time after 1945 to be more useful, or maybe there's a simpler explanation?

More likely it was once a mess hall, transplanted from the old, now gone, wartime Greta Army Camp.

But many old buildings often have strange backstories.

Later, Hunter aviation historian Bill Hitchcock, of Dudley, was also stumped about the largely intact structure.

"There was a bloke called 'Bruce' who flew a Piper Comanche aircraft from up that way," Hitchcock, now 92, remembered.

"He used to fly regularly to Coffs Harbour.

"He was killed in an air crash, but he would have kept his aircraft somewhere there.

"He might have used a private airfield."

Reality can be far odder than fiction.

After all, a former aircraft hangar at what was once Newcastle Aerodrome (1929-63) at District Park, Broadmeadow (now the home of the Knights and Jets), was kept on its original site to be used a paint workshop.

There is also a small, private airstrip still at Wallsend.

Afterwards, Hitchcock's comments rang other bells.

Wasn't a big Hunter hangar once shifted down to busy Bankstown Aerodrome, near the Georges River in Sydney, to be re-used there?

It seems unlikely, but it's probably true.

According to the NSW Office of Environment and Heritage, "it is understood (Bankstown) is the only air base in NSW to include more than three types of World War II-era hangars surviving in-situ and has (also) retained a relatively large number of (other) WWII buildings".

Of at least 12 hangars around the four-runway aerodrome, six are huge Bellman-type hangars, the inventory shows.

Manufactured by Lysaght's, the English-designed Bellman hangar (from 1936) were good because they could be erected or dismantled by unskilled personnel.

A number of WWII Nissen huts once used for housing there were recycled at new sites.

Meanwhile, the secret location of one of several wartime emergency airstrips in Port Stephens has recently resurfaced. Or has it?

Part of a 1966 aerial picture (pictured) from the Tomaree Museum Association seems to clearly show the surviving rectangle of an historic runway running parallel to the road into Taylors Beach.

The site is now overgrown, but some locals insist there's never been an airstrip at Taylors Beach.

They say it's being confused with a long-gone salt works, which, by comparison, is clearly remembered.

Saltwater was pumped onto a long, tar surface, left to evaporate over hours and then the salt was harvested.

All of which brings me to possibly to the strangest airfield tale of all.

While I was researching this article, my lovely, long-suffering wife, Lyn, floored me by telling of a major, but once hidden, WWII airstrip at Woy Woy.

She would know for sure, having come from around there.

"But there's nothing left today, the land is covered with houses," Lyn said.

"This 1942 airstrip site was at today's Trafalgar Avenue, Woy Woy.

"I particularly remember the red gravel laid down to form the runway surface over a base of crushed sandstone after the bush was bulldozed.

"My parents always thought though it was a pity to lose such a valuable Central Coast facility just to provide houses."

She's 100 per cent right about the peninsula airstrip and its location.

It was home to the Royal Navy Fleet Air Arm during World War II and used for emergency repairs and refuelling by aircraft flying up and down the seaboard.

But to learn more, I turned to Woy Woy historian and blogger Steve Spillard.

During his research, old time locals divulged that large American bombers often landed at Woy Woy.

The aircrews and aircraft from British aircraft carriers also regularly visited as part of a rotation program during the war years.

Spillard writes that the Woy Woy strip was originally designed to deploy eight medium-sized bomber aircraft.

These were housed in special bays with U-shaped soil walls and camouflage nets suspended above each hideout.

To further obscure the site, the taxiways leading to the runway used existing streets, with some new ones also built.

Spillard writes that, on other roads, telegraph poles (today's equivalent of power poles) were removed to accommodate the wingspan of large aircraft.

As the threat of wartime enemy invasion receded, the airfield become an emergency landing ground instead.

Spillard reports that since WWII, two large radial type aircraft engines have been dug up in the area.

It was apparently military practice in the 1940s that as engines were removed and replaced with new parts, the original items were buried nearby.

And some visiting US aircrews must have also really liked their Woy Woy stopover.

Military police once pounced on a house in Umina after three airmen deserted their bomber and even sold their uniforms to the locals to better blend in with the community.

By 1949, the airfield was no longer needed.

Spillard said that before new housing was erected, the site was used for an annual motorbike race. Many locals also learned to drive on the former airstrip.

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