Wop May, the Fort Vermilion Mercy Flight, and the January Run Through the Alberta Wilderness That Saved a Town from Diphtheria

On January 2, 1929, Canadian bush pilot Wilfrid “Wop” May and co-pilot Vic Horner flew a Bellanca monoplane 250 miles through subarctic Alberta - in temperatures between 30 and 50 degrees below zero Fahrenheit - to deliver diphtheria antitoxin to the isolated settlement of Fort Vermilion. The flight saved children from a deadly outbreak and stands as one of the defining moments of early Canadian aviation. May had already survived being chased by the Red Baron over the Western Front. This time, his enemy was the cold.

Who Was Wop May?

Wilfrid May was born in 1896 and grew up in Edmonton, Alberta. His childhood nickname - Wop - followed him through his flying career and into the history books. By the time he walked out to his airplane that January morning in 1929, he had already lived through experiences that would define most pilots’ entire careers.

He was a decorated World War I fighter ace with 13 aerial victories. He was one of the most experienced bush flyers in western Canada. And he had survived one of the most famous air combat incidents of the entire war - on his very first patrol over the Front.

The Day the Red Baron Chose the Wrong Target

In April 1918, May flew his first operational combat mission over the Western Front in a Sopwith Camel. His squadron commander’s orders were plain: if you get into trouble, break off and come home.

May eventually followed those orders. He got drawn into fighting over the Somme Valley, found himself in a turning duel he could not win, and broke for home. Behind him came a German Fokker triplane, painted red and instantly recognizable: Manfred von Richthofen - the Red Baron, the most decorated fighter pilot in history, with 80 confirmed aerial victories.

May ran at full throttle, skimming low over the trees and the Somme River, with Richthofen closing from behind. His flight leader, Roy Brown, spotted the pursuit, dived in, and fired. The red triplane went down near Vaux-sur-Somme.

Whether the fatal shot came from Brown’s guns or from Australian ground troops positioned along the river has been debated for more than a century without resolution. What is not disputed: May flew out that morning as the newest pilot in his squadron and flew back having survived the encounter that ended the career of the most famous fighter ace in history. He went on to score 13 aerial victories of his own before the Armistice.

The Isolation of Fort Vermilion

Fort Vermilion sits on the Peace River in northern Alberta, and it is old - the Hudson’s Bay Company had operated a trading post there since the early 1800s. But age and connection to the outside world are different things.

Edmonton is roughly 300 miles south of Peace River. Peace River is the northern terminus of the rail line. Fort Vermilion sits another 250 miles north of Peace River, with no road, no rail, and no practical overland route in winter. In summer, the river allowed boat travel. In January, a dogsled team moving hard could cover that distance in ten days or more - if the trail held and the temperature didn’t drop so far the dogs couldn’t work.

That isolation was survivable under ordinary circumstances. In a medical emergency, it was a death sentence.

The Diphtheria Outbreak and the Race for Antitoxin

Diphtheria is a bacterial infection that produces a thick, leathery gray membrane in the throat. It can thicken until it closes the airway completely. Children are the most vulnerable. It spreads efficiently through close-quartered communities - exactly the kind of population crowding together for warmth through an Alberta winter.

By the late 1800s, scientists had developed an effective antitoxin. By 1929, it was widely available in Edmonton and Peace River. Fort Vermilion might as well have been unreachable.

In late December 1928, diphtheria cases appeared near Fort Vermilion. The regional physician was Dr. Mary Percy Jackson, who had come from England to practice medicine in northern Alberta and was one of the only doctors serving that entire stretch of the north. She sent word south immediately: she needed antitoxin, and she needed it fast.

The Alberta government moved quickly. The antitoxin went onto the northbound train. The train reached Peace River - end of the line - and stopped.

What the Flight Actually Demanded

Commercial Airways, May’s Edmonton-based employer, was asked whether the gap between Peace River and Fort Vermilion could be closed by air. May said yes. Vic Horner would fly with him as second pilot. They would pick up the antitoxin in Peace River and carry it north.

The aircraft was a Bellanca monoplane - a capable, reliable machine with a solid radial engine. In autumn, a reasonable choice. In January at 40 below, a different proposition entirely.

Engine oil thickens dramatically in extreme cold. Below a certain temperature it will not flow well enough for an engine to turn over at all. Before flight, the oil had to be heated and the engine pre-warmed - often with a fire kept burning beneath the cowling - and once running, the engine had to stay running. A restart in those conditions was not guaranteed.

Carburetor icing, fuel line freezing, and instrument failure from thermal contraction were all real possibilities. An engine failure over the boreal forest meant one option: try to put the Bellanca down on river ice riddled with pressure ridges, overflow ice, and sections where the current ran too fast to freeze solid all the way across.

And then there was the cargo. A frozen vial of antitoxin is useless - it cannot be thawed and administered. Everything they were risking their lives to deliver had to stay warm enough to remain viable across three hours of subarctic flight. May and Horner packed it carefully, kept it close to what warmth the cockpit could offer, and flew.

The Flight North

They departed Peace River on January 2, 1929, heading northwest. Below them stretched roughly 250 miles of boreal forest, the frozen Peace River the only reliable landmark in a world of dark conifers and snow. The winter sky over northern Alberta in January is low and gray. The horizon blurs. The flat light flattens depth perception with it.

The engine was the thing that mattered. May and Horner listened to it the entire way north - the sequential percussion of each cylinder at cruise power, building the sound of normal in their ears so that any deviation would register before they could name what they’d heard.

The engine kept running.

Approximately three hours out of Peace River, they came over the last bend of the river. Fort Vermilion was below them. They identified a usable stretch of frozen Peace River and brought the Bellanca down.

The antitoxin was unloaded. It was still viable. Dr. Jackson received it and began treatment.

The children survived. The outbreak was contained.

May and Horner turned around and flew south before the light gave out, back to Peace River that afternoon. They returned to Edmonton the next day. The entire round trip, including stops, took two days.

There was no press conference. No formal ceremony. They filed their paperwork and went back to work.

What Came After

May continued building one of the more remarkable careers in Canadian aviation. He co-founded his own aviation company, which was eventually absorbed into the larger commercial network connecting Canada’s north to the south through the 1930s.

In 1932, he was back in the northern sky - this time flying aerial observation during the manhunt for Albert Johnson, the “Mad Trapper of Rat River,” coordinating search operations by air over the Northwest Territories in February. That particular assignment tells you something about how Wop May felt about winter flying.

He died in 1952. Edmonton’s City Centre Airport - Blatchford Field, the same field where he had checked the thermometer that January morning in 1929 - carries his name.

Fort Vermilion is still there on the Peace River. It remains one of the most remote communities in Alberta.

Why This Flight Still Matters to Pilots

The Fort Vermilion mercy flight is not primarily a story about heroism, though it has plenty of that. It is a story about what aviation actually is.

May was a decorated ace with a reputation that could have sustained a comfortable life on the ground. Instead he went north, learned the bush routes, built genuine expertise in operating aircraft in conditions most pilots would never attempt, and understood the rivers and the light and the behavior of cold engines in ways that could only come from hard experience.

When Fort Vermilion needed help, everything that made the flight possible was knowledge accumulated over years: how to keep an engine warm enough to start, how to read river ice from altitude, how to protect fragile cargo across three hours in temperatures that would have destroyed it otherwise.

The airplane was not a vehicle for speed or spectacle. It was the only machine that could close a gap that would have killed children. That understanding - aviation as a tool for going where nothing else can reach, when nothing else can reach in time - defined the Canadian north and remains relevant to anyone who flies remote country today.

Key Takeaways

• Wop May was a WWI ace with 13 aerial victories who survived being chased by Manfred von Richthofen - the Red Baron, 80 confirmed kills - on his very first combat patrol in April 1918.
• On January 2, 1929, May and co-pilot Vic Horner flew a Bellanca monoplane from Peace River to Fort Vermilion - approximately 250 miles in temperatures of 30–50 degrees below zero Fahrenheit - to deliver diphtheria antitoxin.
• The antitoxin had to remain unfrozen throughout the flight; a frozen vial cannot be thawed and used.
• The one-way flight took roughly three hours; the full round trip was completed in two days.
• The flight is a foundational example of bush aviation’s defining purpose: reaching communities that no other form of transportation could serve in time.