ON SEPT. 13, 1943, HIGH ATOP THE Apennine Mountains in Italy, one of the most daring rescue missions of the Second World War took place.

After a humiliating arrest by his own party underlings, the fascist leader Benito Mussolini found himself confined to the Campo Imperatore Hotel in the Italian Alps. On the personal orders of the Fuehrer himself, a team of German paratroopers and SS commandos assigned the task of springing the deposed dictator from his mountain top prison. The mission called for a glider-borne strike team to crash land onto a tiny patch of ground near the front of the hotel and then assault the building to carry out the rescue. Nine German DFS 230 gliders carrying nearly 100 troops took part in the operation. Following the attack, which was completed without a single shot being fired, the rescued dictator was hurried to a waiting single-engine Fi-156 Storch and whisked to safety. Although the raid was one of the more audacious wartime operations undertaken using gliders, it wasn’t the only one. In fact, both the Allies and the Axis powers produced thousands of the vehicles and used them in missions both large and small throughout the conflict.

In many ways, gliders were the optimal choice for airborne operations. Troops dropped by parachute risked being scattered over vast areas, while gliders could land hundreds of heavy infantry with a much greater degree of precision. They also afforded a better chance of surprise. Dozens of transport planes rumbling overhead signalled the arrival of paratroopers; gliders could be released much farther from their objectives and would descend silently, often landing undetected. And while parachute infantry typically went into battle only with what they could carry on their backs, glider-borne troops could be inserted behind enemy lines with heavier equipment including jeeps, mortars, anti-tank guns and even specially designed tanks.

To be sure, wartime gliders were often as flimsy as kites and were constructed using little more than canvass stretched over wooden frames. They needed to be light enough to be towed into the skies by other aircraft and since most varieties were effectively disposable (i.e. used once and abandoned), durability wasn’t much of a consideration.

The gliders were pulled aloft by bombers or transports using cable tethers. Once towed to the target area, the two-man crews would cut their engineless crafts loose and make a controlled ‘crash’ landing. Once on the ground, troops and equipment could be offloaded and sent into action. And unlike conventional pilots, glider aircrews were often expected to fight alongside the ground forces after landing.

Tens of thousands of gliders would be used in the war and airlanding regiments would see action in no fewer than eight major operations in all major theatres of the war. Eventually, military gliders would be rendered obsolete by helicopters, but for a short time, they were essential.

Here are some other fascinating facts about the glider war.

• Germany was the first to use gliders in combat. On May 10, 1940, commandos crash landed on the roof of the seemingly impregnable Fort Eben Emael in Belgium. As many as 500 paratroops took part in the surprise attack, using up to 50 ten-seat DFS 230 gliders. Once atop the fortress, specially trained commandos overwhelmed the defenders with satchel charges and flamethrowers. While the Germans sustained nearly 25 percent casualties, the mission was a success.

• The first major Allied glider mission of the war far less successful. In June 1943, a force of more than 140 craft left Tunisia to land British troops on various targets as part of Operation Husky, the invasion of Sicily. While some of the gliders reached their targets, high winds and enemy flak scattered a number of the tow planes. Sixty-five gliders were released too soon and went down over Mediterranean. More than 250 British troops drowned in the disaster.

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  The most abundant military glider to be produced was the American Waco CG-4. More than 13,000 were manufactured between 1942 and 1945 for about $15,000 each — about a fifth of the cost of a C-47 transport plane. Each Waco could carry more than a dozen fully armed troops or a single jeep. Its maximum speed was 150 mph (240 km/h) and it could land on rough terrain in as little as 600 feet. Not all Wacos were used – thousands were declared surplus in 1945 and made available for sale. Many Americans bought unused Waco gliders for $75 each after the war. Civilian buyers weren’t at all interested in owning the disassembled aircraft, but found that the shipping crates in which they were packed made excellent backyard toolsheds.

• The workhorse of the British Army’s glider forces was the Airspeed Horsa. More than 3,600 were produced beginning in 1941. Each could carry as many as 30 troops, a six pounder artillery piece with crew, or up to four tons of equipment.

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  One of biggest gliders of the war was the Messerschmitt Me-321 Gigant. Designed specifically for the invasion of Great Britain, the 100-foot long craft had a wingspan of 180 feet. It could carry 22,000 lbs. of cargo or 120 fully equipped troops. While 200 of these massive birds were built, they were never used in any major operation, largely because transport planes large enough to tow them were so scarce. By 1942, all of the Gigants were mothballed. Amazingly the Germans were working on an even larger glider – the Junkers Ju-322. A massive flying wing design, it could haul up to 140 troops. Only two prototypes were built.

• The Japanese military also invested heavily in gliders, building nearly 1,000. It never deployed them in any offensive role. The most numerous Japanese glider was the Kokusai Ku-8.

• Allied glider infantry regiments, like the U.S. 325^th, 327^th and the 401^st GIR or the British 1^st Airlanding Brigade, never achieved the notoriety of their airborne cousins. In fact it wasn’t until their contribution to the Normandy invasion that troops in American glider units received the same danger pay awarded to paratroopers.

• The largest glider operation in history was Marketgarden. During the failed September 1944 assault on the Rhine, more than 14,000 troops (nearly 40 percent of the total airborne units taking part in the mission) would be dropped into Holland by glider. Approximately 3,000 craft would take part in the mission. Because of the high demand for glider operators, most of the Wacos and Horsas taking part were sent up without co-pilots.

• Not all gliders were for landing infantry. Germany’s experimental Blohm & Voss BV-40 was designed to function as an ultra cheap fighter aircraft. After being towed aloft in advance of an Allied bombing raid, BV-40s would be cut loose en masse high above enemy formations and streak downwards at 900 km/h (560 mph) making surprise attacks on their prey using twin 30 mm cannons. The same firm also engineered the BV-226 (aka BV-246) an unmanned glide bomb that was to be released by a German bomber to deliver a 960-lb. warhead to a target 130 miles (210 km) away. By early 1945, designers were working on a guidance package that could detect radar sources and steer the bomb right to an enemy transmitter. The U.S. Marines were interested in the Bristol XLRQ-1 glider, an armed amphibious craft that could take off and land on water or a beach and carry 24 troops. Only two prototypes were produced. The British tested a motorized version of the Hamilcar that would be effective for high altitude operations where thin air made it tough for transport aircraft to tow the craft. Models with piston engines and even rocket pods to assist with take off were tested. The Americans tested a glider based on engineless airframe of a C-47 Dakota. While the design could carry heavier loads and more troops at higher speeds, the experimental glider, dubbed the Douglas XCG-17 was unsuitable for use on unprepared surfaces, unlike the other tested glider designs.

• More than 5,000 glider pilots were trained by the United States military alone in World War Two. Glider aircrews suffered casualty rates exceeding 30 percent. Most of these aviators were trained at a facility in Lubbock, Texas. Today, the city is home to the Silent Wings Museum, which is dedicated to preserving the memory of these forgotten fliers.

(Originally published on July 1, 2013)