Wop May, the Fort Vermilion Mercy Flight, and the Open-Cockpit Race Against Diphtheria in Forty Below

On January 2, 1929, Canadian aviator Wop May and his partner Vic Horner flew an open-cockpit Stinson biplane more than 600 miles north of Edmonton through temperatures approaching 40 degrees below zero Fahrenheit to deliver diphtheria antitoxin to a dying community at Little Red River, near Fort Vermilion, Alberta. The children survived. The flight changed what Canadians understood aviation to mean.

Who Was Wop May?

Wilfrid Reid May - “Wop” was a childhood nickname that stuck when a younger cousin couldn’t manage “Wilfrid” - was already one of the most famous aviators in Canada by 1929. His fame came not from bush flying but from a single afternoon over the Western Front eleven years earlier.

On April 21, 1918, May was on his very first combat patrol over the Somme valley in France. He was 21 years old, flying a Sopwith Camel, under strict orders not to engage the enemy. He engaged the enemy. A turning fight with a German triplane left him low, fast, and out of ammunition - blazing across the front with a jammed machine gun.

Behind him, closing fast, was Manfred von Richthofen - the Red Baron, 80 victories, the most feared pilot on the Western Front. Trailing Richthofen in turn was May’s squadron commander, Royal Flying Corps Captain Roy Brown, who had spotted the chase and dove in pursuit.

What happened next has been disputed ever since. Whether Brown fired the fatal shots or whether Australian machine gunners on the ground brought Richthofen down remains unresolved. But von Richthofen’s Fokker triplane came down in Allied territory. May flew back to the aerodrome shaking so hard he could barely taxi.

From the Western Front to the Northern Bush

May returned to Edmonton after the war. Like many pilots who came back from the Western Front, he found civilian life too small and too flat. The bush country of northern Alberta and the Northwest Territories offered something closer to the flying he understood - routes that followed frozen rivers because rivers were the only landmarks worth trusting, forced landings into unbroken spruce forest with no hope of rescue for days, and tools kept within reach in the cockpit because if the engine quit, you were also the mechanic.

By 1929, May was running commercial air operations out of Edmonton with Vic Horner - hauling freight, carrying passengers to remote mining camps and trappers’ outposts, surveying wilderness that had never been photographed from the air.

The Diphtheria Outbreak at Little Red River

In early January 1929, diphtheria broke out in the settlement at Little Red River, near Fort Vermilion - roughly 600 miles north of Edmonton. Diphtheria closes the throat. In a settlement with no hospital, no roads, no railroad, and no reliable communications, it was a death sentence.

The nearest antitoxin supply was sitting in a medical depot in Edmonton. The only conventional route north in January was by dogsled - a trip measured in weeks. The medicine would arrive in time to bury the dead.

Someone suggested the airplane.

May and Horner said they would go.

What the Flight Actually Demanded

The aircraft was a Stinson biplane with an open cockpit. No enclosed cabin. No heater. At cruise speed, the slipstream hit the pilots in air already cold enough to freeze exposed skin in minutes. At altitude, heading north, the temperature dropped well below what it was on the ground in Edmonton - itself already around 20 below zero Fahrenheit.

The antitoxin had to stay liquid. If it froze, it was worthless and the flight meant nothing. May and Horner wrapped it carefully and held it against their bodies during portions of the flight.

Navigation was by landmarks and dead reckoning, with no radio contact and no instrument approach at the other end. There was no Fort Vermilion airport - only a stretch of frozen river and whatever flat ground May could identify from altitude.

The radial engine required constant monitoring. In extreme cold, oil thickens, cylinders grow reluctant, and an engine running cleanly at altitude can start to labor without warning. A failure over that country meant putting down in unbroken spruce with no clearing and no rescue.

They stopped to refuel at remote outposts along the route. Every stop meant shutting down, fueling from cached drums, and coaxing a cold-soaked engine back to life. Starting a radial engine at 40 below is not a given - the oil runs thick as molasses and the cylinders don’t want to fire.

Every time, it caught.

The Hands That Couldn’t Feel the Stick

May wrote afterward that he lost feeling in his hands well before they reached Fort Vermilion. Not pain - the sensation simply stopped. He flew by habit and muscle memory, by years of handling an airplane in hard conditions, because his fingers were no longer reporting back.

He could feel himself moving the controls. He could not feel the controls.

He and Horner traded off flying portions of the route. Even in the back cockpit, the cold worked on your judgment, and judgment was the only thing keeping you alive out there.

Arrival and Outcome

They reached Fort Vermilion on January 2, 1929. May found a usable stretch of river ice, came down in a long flat approach over the trees, and stopped the Stinson in the snow.

The settlement came out to meet them. The doctor was waiting.

The antitoxin reached the patients that same day. The children who had been sick survived. No new cases developed after treatment arrived. The outbreak was over.

May and Horner turned around and flew back to Edmonton.

Why the Fort Vermilion Flight Mattered Beyond the Lives It Saved

When they landed in Edmonton, reporters were waiting. The story spread to front pages across Canada and into the United States within days - the Edmonton Journal, the Globe and Mail, wire services across the continent.

But the significance ran deeper than the headlines. Before Fort Vermilion, the airplane was still largely a curiosity in Canada’s north - something you watched at a summer air show or read about in the newspaper. After Fort Vermilion, people began to grasp that aviation wasn’t just machinery for adventure or for war.

For communities with no roads, no railroad, and no reliable winter supply - no way in or out once the freeze came - the airplane was the only thing that could close the distance fast enough to matter. Bush pilots weren’t romantic figures to the people who actually needed them. They were infrastructure. They were the supply chain. They were the reason a child in a settlement 600 miles from a city could access the same medicine as a child in Edmonton.

Aerial Pursuit: The Mad Trapper of Rat River

May continued flying the north through the 1930s. In 1932, the Royal Canadian Mounted Police brought him a new problem: Albert Johnson, known to history as the Mad Trapper of Rat River, had killed an RCMP officer and vanished into the Yukon wilderness in the dead of winter. Johnson was moving on foot across open tundra at temperatures below minus 40 Celsius, faster than pursuit parties could follow by dogsled.

May flew reconnaissance over the Yukon, tracking Johnson from altitude and relaying his position to ground parties below. It was one of the first times in history that an aircraft had been used in active pursuit of a fugitive - aerial surveillance, in 1932, in country that made the Fort Vermilion run look like a practice flight.

Johnson was cornered and killed in late February 1932. The Mounties closed the case in part because May could see him from above when no one on the ground could find his tracks.

The Standard He Left Behind

When the Second World War came, May ran training programs for the Royal Canadian Air Force, passing along twenty years of operating experience in conditions where the margin for error was essentially zero.

He died in June 1952. He was 55 years old.

The routes he proved could be flown, the understanding of what aviation could do for isolated communities, and the standard he set for operating in extreme conditions - those lasted far longer than the headlines.

Key Takeaways

• Wop May flew the Fort Vermilion mercy flight on January 2, 1929, covering more than 600 miles north of Edmonton in an open-cockpit biplane at temperatures approaching 40 below zero Fahrenheit
• The mission delivered diphtheria antitoxin to the Little Red River settlement, saving children who would have died before a dogsled could make the round trip
• May was already famous as the pilot the Red Baron was chasing when von Richthofen was shot down on April 21, 1918 - on May’s very first combat patrol
• The Fort Vermilion flight shifted public understanding of aviation from wartime curiosity to critical infrastructure for Canada’s isolated northern communities
• In 1932, May pioneered aerial surveillance during the manhunt for the Mad Trapper of Rat River - one of the first recorded uses of aircraft in active fugitive pursuit