He had bartered Army provisions for the artefacts and ingeniously packed them in a long tube of several metal cylinders welded together.

The tube was then wrapped in military canvas for the voyage to America.

In a joint effort facilitated by the United States embassy in Papua New Guinea and US congresswoman Jan Schakowsky, the items are now being repatriated to the newly renovated National Museum and Art Gallery in Port Moresby.

Grace Vele, a curator at the museum, calls the artefacts "rare antique items of cultural significance."

Embassy personnel refer to PNG’s national museum as similar in stature to the US Smithsonian Institution.

"My father never spoke much about his time in the war,” said Len Happ’s son John. “But we came to learn that he meticulously saved his military orders, correspondence and photos and stored them away in his navigation case.

“It was a surprise to learn that he was a combat pilot."

John inherited the navigation case and his father's memorabilia shortly after his father died. Among the collection returned to PNG are historic photos from the Lae area and its people.

And there is also the 1.5 meter long wooden bow with several wooden spear-like arrows adorned with unique hand carving. They are all still in excellent condition.

A letter from Captain Happ to his family around January 1944 describes some of the interaction with Papua New Guineans:

"From nearby native gardens we get cocoanut and such fruits as bananas, limes, pineapple and panpan (like our musk melons). In a village farther distant the natives raise pretty fair corn and the squadron has had one meal of corn on the cob from their fields. It was a real treat."

Following the attack on Pearl Harbor in December 1942, Japan invaded many colonies in Pacific Asia, including New Guinea.

The key battle to stop Japan took place along the 2,400 kilometer length of the massive island of New Guinea.

Captain Happ flew 64 combat missions out of Gusap and numerous long distance supply missions to Australia.

The Battle of New Guinea is now known as the greatest campaign victory in the history of the US Air Force.