Wop May, Vic Horner, and the January Mercy Flight That Carried Diphtheria Antitoxin to Fort Vermilion

On January 2, 1929, pilot Wilfrid “Wop” May and his colleague Vic Horner departed Edmonton, Alberta in an open-cockpit biplane carrying diphtheria antitoxin pressed against their bodies to keep it from freezing. The temperature was forty below zero. Their destination was Fort Vermilion - roughly 350 miles north - a community that, in winter, was otherwise accessible only by dog sled. They got there. The medicine was warm. The children at risk were treated, and the outbreak was contained.

Who Was Wop May?

To understand the January mercy flight, it helps to understand the man who flew it.

April 21, 1918. Second Lieutenant Wilfrid Reid May is on his first combat patrol over the Western Front. His flight leader, Roy Brown, had given him clear instructions before takeoff: if things get complicated, break off. You’re still learning.

May spotted an Albatros biplane below him and did what any twenty-three-year-old trained for that moment would do. He attacked. He missed. He overshot - and drew the attention of Manfred von Richthofen, the Red Baron, with 80 confirmed kills. For several minutes over the Somme River, May fought to stay alive while Richthofen worked to add number 81 to his tally. Brown dived to help. Richthofen was killed - by Brown’s guns, by Australian ground fire below, or some combination; historians have debated it for a century. May survived.

He landed and was violently ill on the airfield. He was twenty-three years old and, by any reasonable accounting, should have been dead.

A Decade of Building Aviation in the Canadian North

By 1929, May was thirty-four, running Commercial Airways Limited out of Edmonton. For most of the 1920s he had been flying freight into Canada’s north - bush flying in its truest form. You loaded whatever needed to move. You flew from a map that was only slightly better than a guess for anything north of the Peace River. Navigation was dead reckoning and landmarks, when you could find them. Fuel was sometimes drums cached in summer. Weather reporting was essentially nothing.

The aircraft of the era demanded constant attention. Open or barely-enclosed cockpits. Basic instruments, when they worked. Engines that did not like cold - and the Canadian north is not kind to engines in January. Oil thickens. Fuel systems ice up. The flights ended on your terms, or they ended on the engine’s terms.

May and Horner flew anyway, because the freight needed to move and the people in those northern communities needed what was on the airplane.

The Diphtheria Outbreak at Fort Vermilion

Fort Vermilion sits on the Peace River in northern Alberta. In 1929 it was one of the oldest European settlements in the province and one of the most isolated. Summer brought riverboats. Winter froze the river, stopped the boats, and reduced the supply chain to dog sled - roughly thirty miles a day in decent conditions, meaning ten days or more from Edmonton.

In the winter of 1928–1929, diphtheria broke out in the area.

Diphtheria is a bacterial infection of the upper respiratory system. It produces a membrane - a growth of bacteria and dead tissue - across the throat and airway. In severe cases it suffocates the patient. Children are especially vulnerable. The antitoxin was effective, but it had to arrive viable: a biological serum that could not be allowed to freeze. Frozen antitoxin was useless antitoxin.

The local physician, Dr. Harold Hamman, sent word. It traveled slowly - settlement to settlement until it reached a telegraph line - and eventually reached Edmonton and the provincial government. Someone in that chain called Wop May.

The Flight: January 2–3, 1929

May said he would go. He talked to Horner. Horner said he would go.

They departed Edmonton on January 2, 1929, carrying the antitoxin packed as carefully as possible. Then they did what technology could not do for them: they held the medicine against their own bodies, relying on body heat to keep the serum viable. In an open cockpit. At altitude. At forty below zero.

At minus forty, the Fahrenheit and Celsius scales meet - they are the same number. Exposed skin frostbites in minutes. The air feels like breathing something hostile. And they were not standing still. They were moving through it at eighty to ninety miles per hour.

They had proper cold-weather flying gear for the era: fur-lined suits, goggles, every layer available. It was not enough to be comfortable. It was enough to survive.

The route north was not direct. They stopped to refuel, check the aircraft, and assess conditions. The January light at those latitudes comes in low and flat, throwing shadows that lie about the terrain. Blowing snow erases the horizon. The white ground and white sky merge into something that offers no reference at all. They navigated by dead reckoning - heading, time, altitude, and the occasional landmark visible through the cold haze - using knowledge of that country built from years of flying it.

They reached Fort Vermilion. The antitoxin was warm when they landed. The children at risk received the medicine. The outbreak was contained.

May and Horner then turned around and flew back to Edmonton.

Seven Hundred Miles, Two Days

The round trip covered approximately 700 miles over two days, with an overnight stop at Fort Vermilion. When they returned to Edmonton, crowds met them. The newspapers ran the story. The province celebrated.

May’s response was to turn the conversation almost immediately to the operational question: what equipment would serve the northern routes better? How do you build a supply chain regular enough that the next outbreak doesn’t have to be an emergency?

That orientation - toward the operational problem rather than the heroic moment - is what separates the pilots who built aviation in the north from the ones who simply flew through it. May understood that what he had demonstrated on January 2 and 3, 1929 was not just a story. It was a proof of concept.

The Airplane as Infrastructure

Fort Vermilion in winter was a community the rest of the world had written off as unreachable. Dog sled was state-of-the-art transportation. The river was the only highway, and it froze for half the year.

The airplane changed the math entirely. It turned 350 miles of frozen wilderness into a few hours of flight. It made the unreachable reachable - not just in emergencies, but potentially, with the right operation, on a regular basis.

Commercial Airways kept pushing those routes north through the late 1920s and into the 1930s. The networks May and pilots like him pioneered became the foundation for air service to remote northern Canadian communities. Routes that had no practical alternative then still have no practical alternative today. You fly to Fort Vermilion, or you do not go at all.

Vic Horner Deserves More Than a Footnote

Horner sat in the same cold, flew through the same conditions, and held up his half of a two-man operation that did not need to exist - because nobody was ordering them to go. Both men chose to go. The choice to put an airplane into a forty-below January morning and fly it north because somebody needed what was on the other end of that route: that choice is the whole story of bush flying. Not the equipment. Not the navigation. The choice.

The bush flying tradition in Canada, Alaska, and every remote corner of the world where the airplane became the only lifeline did not develop because pilots were chasing glory. Most of them were chasing freight rates, fuel costs, and whether the engine would hold together for another five hours. The glory was incidental. The job was the point.

But sometimes the job really was as dramatic as the stories make it sound.

Key Takeaways

On January 2–3, 1929, Wop May and Vic Horner flew diphtheria antitoxin approximately 700 miles round trip from Edmonton to Fort Vermilion, Alberta, at temperatures of forty below zero
The antitoxin could not be allowed to freeze; the pilots held it against their bodies throughout the flight to maintain viable temperature
May had survived being chased by the Red Baron, Manfred von Richthofen, on his very first combat patrol in April 1918 - Richthofen was killed during that engagement
After the mercy flight, May focused not on the heroism of the act but on the operational question: how to build northern air supply chains reliable enough that such emergencies would not be necessary
The routes pioneered by May and pilots like him became the foundation of northern Canadian aviation - communities that had no alternative then still have no practical alternative to air service today