LONDON—An indelible memory of my boyhood is of watching, almost every day, some of the badly smashed up survivors of American bombing raids over Europe limping back to their base near where I lived.

Throughout 1943 and during the build-up to the D-Day landings in the summer of 1944 the U.S. Army Air Force sent swarms of bombers from England over Europe during the day while Britain’s Royal Air Force did the same at night.

After a while my career as an amateur airplane spotter had a routine. It began early in the morning. The B-17 Flying Fortresses, heavy with their bomb loads, climbed slowly overhead to a height where a whole bomber group would form up and then head east over the North Sea.

Hours later they returned, no longer in tight formation but in clusters with obvious gaps where some had been lost. Finally came the stragglers, often with pieces missing from a wing or a tail. I recall one or two that managed to fly with half of a horizontal stabilizer missing or a wing tip half ripped off. Engines ran unevenly, sometimes coughing smoke.

Obviously, I had no idea of the hell that those aircrews had endured. As it turned out, one of the best accounts of that hell was later written by a B-17 navigator, Elmer Bendiner, who flew from that same base, in The Fall of Fortresses, an enduring classic of the World War II bombing campaigns.

Bendiner describes his relief at spotting my hometown, Luton, as he guided his pilot back from one of the war’s costliest raids on the German city of Schweinfurt in August 1943.

Eighteen B-17s had left his base that morning. Only twelve returned. Sixty men were missing. The total for the raid was 600 men missing out of a force of less than 3,000.

“ The arctic temperature of high altitude has momentarily frozen the guns of both. The German pilot, seen clearly complete with a moustache, makes a fly-by and salutes. ”

Wherever the use of air power is discussed, America is accepted as its most formidable exponent. As with those World War II raids on Germany, the military efficacy of bombing large civilian populations is often as controversial as the moral burden that goes with it. But American primacy without air power is today unthinkable.

That is why it is timely to point out that a century ago, at the end of World War I, America had only just realized how slow it had been to acknowledge that war in the air was a large part of the future of war, and one with the potential to decide the outcome of wars—as it did at Hiroshima and Nagasaki in 1945.

At the start of World War I, with military aviation in its infancy, the German military had 260 airplanes, France 156 and Britain 154. The United States Army Aviation Section, as the force was then called, had 23 primitive machines.

Ironically, America, the pioneer of powered flight, was seriously hobbled by its dependence on the Wright Brothers concept of what an airplane should look like—a biplane of basically the same configuration as the one that first flew at Kill Devil Hills in North Carolina in 1903. The last Wright machine was delivered to the military in May 1915, and dropped from the active inventory a month later.

In the fiscal year of 1915 Congress appropriated just $250,000 to military aviation.

As a result, when American airmen arrived in France as the U.S. entered the war in 1917, they had to fly British designed DH-4 biplanes built under license in America by the Dayton-Wright company. For years afterwards the American military flew British- and French-designed machines.

During the 1920s, as peace seemed to settle permanently over Europe, America was distracted and withdrew into itself while the flappers danced to a new beat before the Great Depression ravaged the economy. Military aviation continued to be neglected. But in the 1930s a handful of American companies, led by Boeing in Seattle and Douglas and Lockheed in California, revolutionized commercial aviation.

When war in Europe again loomed in the 1930s it was the technology developed to produce the new, sleek transcontinental airliners that was readily transferable to warplanes, transforming them. Boeing, for example, developed the B-17 as America’s first modern four-engine bomber using innovations from its early airliners.

In late June 1941, barely five months before Pearl Harbor, the new Army Air Forces were formed with a target of having 7,800 combat airplanes by mid-1942. After Pearl Harbor an industrial juggernaut pushed production way beyond that level, using 15,000 plants across the country, the major ones converted from car production.

Unnoticed at the time was a large crate that arrived at the General Electric plant at Lynn, Massachusetts, on Oct. 4, 1941. It contained the prototype of a jet engine, an innovation developed and built in Britain, to be produced under license in the U.S. For a cost of just $800,000 America entered the jet age through a gift from Britain.

I thought of this history of collaboration when I visited an airfield just an hour’s drive north of London. The field at Duxford, near Cambridge, was a key R.A.F. base during the Battle of Britain in 1940, and later it was home to some of the first American airmen sent to Europe. Today it is the aviation section of Britain’s impressive Imperial War Museum, and one part of it is devoted to American air power, including the groups who were based in Britain during World War II.

There are three large video arrays recording the names of nearly 30,000 US airmen and women who died while based in Britain. Etched into a corridor of Plexiglas panels are the silhouettes of every airplane lost in the skies over Europe, pinned like butterflies between glass.

War devises many ways for men to die. In the air, men were part of a machine in a way that was unique, and the machine frequently died with them, as horses did under medieval knights. Death in bombers was more random. They often made it back with some crew members dead or badly injured. Crews watched as other bombers blew up, broke up or dived to earth. Parachutes sometimes opened and sometimes did not.

“I clocked the fall of fortresses” Bendiner wrote, “and, when someone sang out the number of parachutes that opened, I tried to keep a score. But I never pretended that I could be precise at such a time, with the mask sitting on my nose, with the tin pot on my head and frost blotting out my view.”

Bendiner’s commander claimed (extravagantly) that on the Schweinfurt raid German losses were far greater than their own—of 300 fighters sent to intercept them, he said, 99 were shot down. Moreover, in the chilling calculations of attrition, America could replace losses far faster than Germany. “Perhaps,” comments Bendiner, “but surely it was easier to replace one small fighter manned by one pilot than to turn out a very complex bomber with a crew of ten.”

Suddenly there is a scene of eerie truce when a German fighter attacks Bendiner’s airplane head-on. Bendiner waits for the flare of the fighter’s guns but they never fire. The B-17’s guns are silent, too. The arctic temperature of high altitude has momentarily frozen the guns of both. The German pilot, seen clearly complete with a moustache, makes a fly-by and salutes.

The most gut-wrenching movie portrayal of the British-based B-17 crews remains Twelve O’Clock High, the 1949 production starring Gregory Peck as a hard-driving commander who eventually cracks up. It uses actual war footage from both sides, including from gun cameras.

The museum at Duxford includes jets from the Cold War and the Vietnam war—some still in use like the sinister black-skinned B-52. But it was the B-17 that drew me as though the images of fleeting shape in my memory, watched from below, had suddenly acquired full substance and could be touched. Against the massive B-52 it seems small, amazing that ten men could take their places inside, distributed between the cockpit, the bomb aimer’s seat in the nose and the gun turrets arranged so the field of fire left no blind spots.

There was a social dimension to the role of the U.S. airmen and women who served in Britain. Many had never traveled outside of the US before; many had never left the counties they were born in. There are photographs at Duxford of some of the cultural consequences of the experience. Airmen instruct British kids on the rules of baseball; the kids attempt to explain the more impenetrable terms of cricket.

In 1942, as the first units were preparing to leave for Europe, someone in the War Department decided to produce a guide to the social customs and habits of the British, as well as commentary on their morale. In seven typescript pages the anonymous author shows a sensitive grasp of a sensitive situation.

“You won’t be able to tell the British much about ‘taking it,’” the writer warns. “They are not particularly interested in taking it any more. They are far more interested in getting together in solid friendship with us, so that we can all start dishing it out to Hitler.”

(This may sound callously jingoistic, but the ethical issues of mass bombing tend to disappear when you have yourself been at the receiving end.)

This is followed by some basic observations that still apply today, such as: “There are fewer murders, robberies, and burglaries in the whole of Great Britain in a year than in a single large American city.”

After explaining that the king had no political power there is a serious caution: “Be careful not to criticize the King. Today’s King and Queen stuck with the people through the blitzes and had their home bombed just like anyone else, and the people are proud of them.

“The important thing to remember is that within this apparently old-fashioned framework the British enjoy a practical, working twentieth century democracy which is in some ways even more flexible and sensitive to the will of the people than our own.”

And there is a pointed tribute to the way British women had stepped into vital roles in the war effort: “They have stuck to their posts near burning ammunition dumps, delivered messages afoot after their motorcycles have been blasted from under them. They have pulled aviators from burning planes. They have died at the gun posts and as they fell another girl stepped directly into the position and “carried on.” There is not a single record in this war of any British woman in uniformed service quitting her post or failing in her duty under fire.”

For Americans then Britain was “over there.” As scores of air bases turned the island country into the world’s largest aircraft carrier an interchange of battle spirit and the two cultures took place on a scale that had never occurred before.

People of all ages and in both nations never forgot this bond. I certainly never have. We had a first-hand view of America at her greatest, of a selfless and courageous ally that had come late to the responsibilities of air power, and finally employed it to devastating effect.