By Dr. Silvano Wueschner, Air University History Office
/ Published March 25, 2019
American bombing attack on the railyard at Chalon, France in spring 1944 turned the facilities into a mass of twisted steel and rubble. Allied operations planers, however, discovered that most railyards required several periodic attacks to keep them unusable. (USAAF archival photo)
An Allied attack on the bridge over the Seine River at Oissell, France, on May 9, 1945, made the bridge unusable. German forces could not repair the Seine bridges fast enough to keep up with their damage/destruction in spring 1944. (USAAF archival photo)
Allied air attack on the cathedral city of Rouen, France on July 9, 1944, destroyed much of the city, including the major bridges, like this one, over the Seine River. (USAAF archival photo)
A photograph, taken by the gun camera of a P-47 Thunderbolt, showing the aircraft strafing a French freight train. The Republic P-47 Thunderbolt was one of the primary tactical aircraft used by the U.S Army. Air Forces for attacks on railyards, freight trains and military airfields during the implementation of the Transportation Plan. (USAAF archival photo)
British Hawker Typhoon ground attack aircraft, armed with four cannons, eight unguided air-to-ground rockets and two 500- or 1,000-pound bombs. The Royal Air Force contributed the Hawker Typhoon for tactical attacks on various types of ground targets during the implementation of the Transportation Plan. (USAAF archival photo)
The twin-engine Martin B-26 Marauder medium bomber, assigned to Ninth Air Force, dropping a string of bombs during a mission. The Marauder, flying at medium altitudes of 10,000 to 15,000 feet with fighter escorts proved to be the most accurate attack aircraft used during the conduct of the Transportation Plan. (USAAF archival photo)
A French locomotive knocked off the tracks at a French rail center after an aerial attack. During the conduct of the Transportation Plan, Allied planners discovered that the German authorities could relatively replace destroyed and damaged freight cars by transferring freight cars from Germany and further east to France. However, destroyed or heavily damaged locomotives were not as easily replaced as the freight cars. (USAAF archival photo)
A photograph, taken by the gun camera of a P-47 Thunderbolt, of an American strafing attack on a German airfield in France. In addition to attacks on transportation targets, Allied aircraft attacked German airfields in France and Belgium. These attacks, combined with the intensifying strategic bombing of industrial targets and cities in Germany, forced the Luftwaffe to withdraw most of their fighters from Western Europe back to Germany. (USAAF archival photo)
By early January 1944, Supreme Headquarters Allied Expeditionary Force, or SHAEF, had begun planning for the greatest seaborne invasion in history, Operation Overlord, the invasion of “Fortress Europe,” scheduled for early June.
General Dwight D. Eisenhower, Supreme Allied Commander, was reasonably sure that the Allies could land sufficient forces to establish a beachhead along the Normandy coast of France during the first critical days of the invasion. However, he wasn’t so sure that these initial forces could sustain itself unless the Allies had air superiority over the landing beaches and could prevent German forces in Normandy from receiving reinforcements.
Eisenhower’s concern led to the development and adoption of the Transportation Plan, conducted from March 6, 1944 to mid-August 1944. The two main objectives were preventing the German air force—Luftwaffe—from interfering in the landings and the establishment of a sustainable foothold and preventing the German forces in France from reinforcing German Army Group B, commanded by one of Germany’s finest tactical commanders, Field Marshal Erwin Rommel, manning the Atlantic wall defenses along the French coast. By August 1944, the Transportation Plan had virtually stopped German military movements during daylight and driven most of the Luftwaffe out of France.
Eisenhower insisted that Allied air forces bring their full weight to destroy German airfields in France and to disable the transportation system that the German army in France in an attempt to drive Allied invasion forces back into the English Channel. However, Lt. Gen. Carl “Tooey” Spaatz, commander of U.S. Strategic Air Forces in Europe, argued that the Allies could best achieve air superiority for the invasion by sustained strategic bombing of synthetic fuel plants and aircraft factories. Such attacks would lure German fighters into the air to defend against the bomber attacks and, thus, hasten the destruction of the Luftwaffe. Spaatz wanted to wait until shortly before the invasion to shift the total effort of the Allied strategic bombers to attacks on the airfields and lines of communication in France.
Royal Air Force Air Marshal Arthur “Bomber” Harris, commander of RAF Bomber Command, also initially opposed the use of his strategic bombers to attack transportation targets as this campaign would divert his bombers from his nighttime strategic bombing of German cities. However, by mid-February, he resigned himself to the plan, and Eisenhower overruled Spaatz.
Professor Solly Zuckerman, an advisor to the British Air Ministry, developed the plan, based on ideas of RAF Air Chief Marshal Arthur Tedder and the “Overlord air plan,” drafted by RAF Air Chief Marshal Trafford Leigh-Mallory. The Transportation Plan, which SHAEF ultimately adopted, would target bridges, rail centers (marshalling yards and repair shops), rail lines and German airfields in France and Belgium.
The main non-military concern in these top-level discussions about the Transportation Plan was the extent of French civilian casualties, estimated at 100,000, which might alienate the French as allies. Eisenhower approached French Maj. Gen. Pierre Koening, commander of French forces in Britain, who, while also concerned about civilian casualties, understood that such casualties were a necessity of the war to liberate France.
On March 6, RAF Air Marshal Charles Portal began the campaign with RAF bombers attacking the marshalling yards at Trappes, Aulnoye, Le Mans, Amiens, Lougeau, Courtrai and Laon, France. Over the next 90 days, the air campaign, carried out by thousands of RAF strategic bombers and Hawker Typhoons and American P-51 Mustangs, P-47 Thunderbolts, B-17 Flying Fortresses and B-24 Liberators, grew in intensity.
Allied aircraft ranged throughout most of western France up to the Seine River and Paris and into southern Belgium to keep the Germans from pinpointing the planned landing sites in Normandy. By June 6, D-Day, these aircraft had flown 29,000 sorties and dropped more than 75,000 tons of bombs on French and Belgian rail centers, destroying 37 and heavily damaging an additional 23. Furthermore, the systematic bombing of major road junctions, bridges, tunnels and rail lines forced the Germans to continuously find alternate routes, which delayed and reduced movements to the Normandy area.
The Luftwaffe was ill-prepared to counter this massive Allied air campaign. It had only about 1,800 aircraft throughout Western Europe, of which about 555 would be usable against the upcoming Allied invasion. Of these, only 50 percent were fighters or ground attack aircraft. Because of the Allied attacks on German airfields in France and Belgium and the intensifying strategic bombing of Germany, the Luftwaffe had pulled most of its aircraft back to Germany by D-Day. As a result, on D-Day, the Luftwaffe mustered only 60 flyable aircraft, which flew only 200 sorties (in comparison to more than 20,000 by Allied aircraft) with negligible results.
By D-day, the Transportation Plan had made daylight movement virtually impossible throughout most of France, Belgium and the Netherlands. According to a June 13, 1944, German Air Ministry report: “The raids have caused a breakdown of all main lines; the coast defenses have been cut off from the supply bases of the interior … large scale strategic movement of troops by rail is impossible at the present time and must remain so while attacks are maintained at their present intensity.
Reports from German army commanders in May and June 1944, interrogation of German prisoners of war and postwar interviews with German senior commanders who served in France all attest to the decisive role of the Transportation Plan to the success of the D-Day landings and follow-on advances of the Allied forces in France