When Allied troops stormed ashore at Normandy 80 years ago today, the outcome of the operation was very much in doubt.
The landing of 156,000 British, Canadian, American, Norwegian and Free French troops was, and remains, the largest amphibious operation in military history. While the complex maritime logistics of Operation Overlord often capture the focus of annual commemorations and historic analysis, it was the revolutionary use of air power that enabled the initial success in the campaign to retake Western Europe.
The Allies’ success in establishing a beachhead in France by the evening of 6 June 1944 was the culmination of a months-long air campaign, which included the development of new aircraft and new tactics.
“Air power is an integral part of that effort,” says John Curatola, a senior historian at the USA’s National World War II Museum.
That air power came in two forms: the long-range strategic bombing of industrial targets; and close-range tactical air support to ground troops. While the former was already being heavily employed when planning for the Normandy invasion began, the latter required developing new aircraft, new tactics and a revolution in military thinking.
Earlier amphibious assault operations at Sicily and the Italian mainland lacked the type of closely integrated air support that was later seen at Normandy, with those preceding battles proving the need for a new way of pairing air power with ground and naval forces.
“The Mediterranean is the classroom that allows the Americans and our allied partners to learn how to work together,” Curatola says.
The 1943 invasion of Sicily was particularly instructive, as the first time Allied forces attempted to land under well-coordinated resistance, including enemy air forces.
American air commanders at the time fundamentally misunderstood what ground forces needed during a seaborne invasion, Curatola argues. Rather than providing tactical air support to troops on the beaches, the US Army Air Force opted to strike strategic industrial and transportation targets far away from the battlefield.
“The air force is more interested in going deep and going long, and they are not over the beach,” Curatola says.
“What happens is the Luftwaffe and the Regia Aeronautica, the Italian air force, can reign over the fleet, and they do,” he adds.
While the presence of Axis air forces was not enough to turn back the invasion of Sicily, the lack of protective air cover disrupted the operation and forced Allied commanders to re-evaluate their approach.
“Two months later at Salerno, the air force was there,” Curatola says of the subsequent invasion of the Italian mainland. “They are over the beaches; they’re intercepting German fighters over the fleet.”
The historian and former US Marine Corps officer says those doctrinal changes formed the basis for what the Pentagon now calls combined arms integration – the synchronisation of land, ground and air forces. That paradigm has since been expanded to include space and cyberspace in the modern era.
“What you see here is that the air force was learning that they had to provide that support to the landing force,” Curatola says of the Italy campaigns. “So at the time Normandy comes around, air power is an integral part of that effort.”
But further changes in aerial strategy were still needed to ensure success against the heavily defended “Atlantic Wall” along the French coastline.
While air commanders in the Mediterranean had learned the importance of close integration with ground forces, British and American officers overseeing the bombing operation in Northern Europe still overwhelmingly preferred striking targets deep inside Germany-controlled territory.
Curatola notes one exception to this were to so-called “crossbow missions” – the targeting of German launch sites lobbing long-range rockets and flying bombs across the English Channel into British cities.
Change would come at the behest of the American general Dwight Eisenhower, the supreme commander of Allied forces in Europe.
Eisenhower had overseen the landings at Sicily and saw the need for more closely integrated air support to protect ground and naval forces. However, when he began planning the invasion of France, Eisenhower encountered resistance to the idea of shifting resources away from long-range bombing of strategic targets.
While Allied air commanders understood the need to establish air superiority over France and the English Channel in order for the invasion to succeed, their existing strategy was to do so by crippling German aircraft production through the use of long-range bombing.
When Eisenhower began planning Operation Overlord, he wanted to redirect those assets toward striking German-controlled transportation infrastructure in France and coastal defence installations – a shift that air force generals resisted.
“He really has to fight with his more strategic-air-minded subordinates,” Curatola notes.
That fight included the creation of an entirely new American command, the US Ninth Air Force, which Curatola says was focused solely on supporting the ground campaign, flying “tactically focused” air interdiction and close air support sorties.
This force would operate lighter bombers like the twin-engined Martin B-26, rather than the four-engined Consolidated B-24 and Boeing B-17 heavy bombers. The Ninth’s tactical forces were also built with troop support in mind, predominantly featuring the Republic P-47 ground attack fighter.
In the Royal Air Force, the ground attack role was filled by the Hawker Typhoon and its derivative the Hawker Tempest.
However, the Allies’ new air strategy also included new fighter tactics for the long-range air forces still flying over Germany.
In the months leading up to Normandy, Allied pursuit squadrons based in the UK would begin actively hunting Luftwaffe fighters, rather than simply providing escort protection for bombers.
This was enabled by the introduction of the famous North American P-51 Mustang, whose Rolls-Royce Merlin engine dramatically improved the range of Allied fighters, for the first time allowing them to accompany bombers penetrating deep into Germany. Although the earlier Lockheed P-38 twin-tail had the ability to reach Germany, the twin-engined fighter had proven ineffective at mitigating serious Allied bomber losses at the hands of German fighters.
With Mustangs arriving to Europe in large quantities, that balance began to change. Whereas the previous Allied strategy for achieving air superiority had been focused on destroying German industrial capacity to produce aircraft, the new fighter tactics of P-51 pilots would actively reduce existing Luftwaffe assets.
This tactic was called “ultimate pursuit” and Curatola says it freed P-51 pilots from having to remain with their assigned bombers.
“They can go pull away from the bomber formations and pursue the Luftwaffe and kill them,” he explains. “It’s a significant change from what preceded it.”
This new air combat strategy was launched in February 1944 with results that were immediate and devastating.
In the first week, US P-51s killed 18% of all Luftwaffe fighter pilots, Curatola says. Over the four months leading up to the Normandy invasion, the German air force, unable to cope with such high losses, became dramatically less effective.
“By the time you get it to June of 1944, most or much of the Luftwaffe is destroyed,” Curatola notes. “That scale has now tipped.”
While Germany still had combat-ready aircraft, the length of time required to train capable pilots prevented the Luftwaffe from fielding an effective air force, particularly in the realm of dogfighting.
Much of the remaining German fighter force was called back to Germany to defend against the ongoing long-range bombing campaign.
When D-Day arrived, Curatola says, the Allies had the airframes, pilots and tactics to “operate with impunity” in the skies over France, facing a far less fearsome Luftwaffe.
D PLUS ONE
The first thrust of Operation Overlord would also come from the sky, in what Curatola calls a “vertical envelopment”.
Some 11,000 aircraft were involved in the invasion, with Douglas C-47 transports dropping British and American paratroopers and glider forces in the early hours of 6 June.
The roughly 23,000 airborne forces who were the first Allied combat troops into Normandy would endure casualty rates more than double those suffered by the 130,000 infantry landing at the beaches.
Although seaborne forces faced well-entrenched defenders, they were largely unopposed in the air.
By the nightfall, the Allies accomplished enough of their landing objectives to establish a beachhead on “D+1”, the day after D-Day. However, it would take two months of heavy inland fighting to eventually break out from Normandy and reach Paris.
That breakout campaign saw further innovations in how aircraft provided support to ground forces, including the use of heavy bombers to attack close-range enemy targets and coordination between pilots and ground troops via radio.
Such practices continue in the 21st Century, with notable examples of Boeing B-52 strategic bombers providing tactical air support to US ground forces in Afghanistan. Specialised tactical air control personnel now commonly embed with ground forces to liaise with pilots overhead and direct aerial munitions.
LEGACY
Twenty year after D-Day in 1964, Dwight Eisenhower returned to Normandy, by that time a former US president, with CBS News legend Walter Cronkite. The pair walked the D-Day landing grounds and inland countryside, where Eisenhower’s troops had struggled for weeks against dense hedgerows and entrenched German defenders.
Standing on a ship overlooking the British landing sector, Cronkite asked Eisenhower if D-Day could have been possible without the air superiority Allied bomb crews and fighter pilots spent months achieving over Normandy.
“Oh no, no,” the five-star general said.
Eisenhower credited the lack of air resistance to both poor weather during the landings and the Allies’ tactic of bombing the grass fields around Normandy to prevent their use as improvised air strips.
“Way back to as far as 200 or 300 miles, we had taken every field that we could find and just pockmarked it so it was unusable at the time,” Eisenhower said.
“All in all we had a day that was free of enemy interference, except that we met on the beach,” he added.
D PLUS 80
Eighty years after D-Day, allied air power is once again on display in Normandy, albeit in a much changed form.
The US Army’s 101st Airborne Division, which jumped into battle behind Utah Beach, traded its parachutes for helicopters in the decades after the Second World War. In 2024, the 101st brought its Sikorsky UH-60 Black Hawks to Normandy, showcasing the ability of rotorcraft to rapidly move troops and equipment over great distances.
Now specialising in what the Pentagon calls air assault, the army says its helicopter-borne force can deliver a 4,000-person brigade of combat soldiers up to 500nm (926km) – a distance many times greater than that between Normandy and England’s south coast.
Lockheed Martin C-130 transports, bearing the commemorative livery of the old US Army Air Corps, have been seen flying low over the old battlefields of Normandy throughout the week. The US Air Force says it has 14 aircraft operating from the Cherbourg-Maupertus airport for the D-Day commemoration.
Some of those will be used to drop nearly 1,000 paratroopers from France, Belgium, the Netherlands, Canada, Germany, and the USA during a 9 June multi-national training event in the village of Sainte-Mere Eglise – an original D-Day objective.
While the equipment and tactics have changed in the eight decades since, many of the strategic principles around air power that were pioneered for the Normandy campaign remain relevant today.
Military forces still seek, and struggle, to achieve air superiority above ground fighting. Now in its third year, the Russia-Ukraine war has settled into a bloody stalemate, with neither side able to effectively control the skies.
That point is not lost on the host of military and political officials assembling in Normandy to mark the 80th anniversary of D-Day. Contemporary members of the NATO alliance are now revisiting many of techniques that made the landings a success, at a time when peace in Europe appears the most tenuous it has been since the end of the Second World War.
