"In those days they went up to 20,000 to 22,000 feet and were certainly hypoxic. Many pilots spoke about the paralysing cold," said Mr Lanham. "They used layers and layers of clothing, including silk gloves, woollen gloves and big mittens. They spoke about the agony of returning circulation after a flight."
Although the pilots wore a light helmet and goggles, their faces were uncovered.
"They used to smear whale blubber on their faces to prevent frostbite."
The bulky garments, including a leather overcoat, were unwieldy in the small cockpits, which also held guns and fuel.
"The butt of the machine-guns would be within a foot or so of the pilot's face," he said. The guns would have to be reloaded mid-flight.
"Imagine trying to do that in minus 40 degrees while you were flying your aircraft."
When things went wrong, there wasn't much that could be done or much time to make decisions.
"At 15,000 to 20,000 feet, they had around two or three minutes to contemplate their fate on the way down. It was common for aircraft to fall apart in mid-air," said Mr Lanham.
"The pilot would have 50 litres of gasoline very close to him. If the aircraft was hit, it was common for it to catch on fire. You had two choices, stay in the aircraft and be burned to death or step over the side. Many chose to step over the side.
"We commemorate these things. We don't celebrate them."
After 27 years in the RNZAF, Mr Lanham retired and, for 12 years, ran his own commercial aviation company in Wellington.
He has also been general manager of the General Aviation Group at the CAA.
Mr Lanham's contribution to aviation was recognised when he was made a lifetime member of the Sport and Vintage Aviation Society.
He will be flying an Albatros D.Va, a Fokker D.VIII and an SE 5a at the air show this weekend.
