About 180,000 planes were lost on operations during World War II ­ shot down by enemy aircraft or anti-aircraft defenses, or lost through navigational error, pilot error or mechanical failure. In addition, perhaps another 60,000 aircraft were lost in accidents during training, ferry flights and other second line activities. To these 240,000 lost in the air must be added perhaps another 40,000 that returned so badly damaged they had to be written off, or that were destroyed during air attack or lost at sea. All told, these losses account for about one third of the aircraft used during the war.

For the Axis powers the losses cut much deeper since they suffered very nearly as many operational losses but fielded just 25% of the aircraft. Of about 200,000 planes fielded by the Axis powers, some three quarters were lost on operations, lost in accidents, written off or destroyed on the ground.

Figure 1 shows estimates for the operational losses of the five major combatants. It also shows how these losses compare to the average number of front-line aircraft present. (We include non-combat aircraft such as transports and reconnaissance aircraft since these incurred their share of operational losses.) This comparison shows that average monthly losses range from just under 10% in the case of the US to about a quarter in the case of the Japanese.

There are four main reasons for the difference in loss rates between countries:

The type of combat engaged in. Some missions were inherently more dangerous than others. Among the Western Allies, strategic bomber missions in Europe incurred loss rates that during some periods averaged 5% on each sortie, while some individual missions incurred 10% losses. Meanwhile, losses among escorting fighters were a small fraction of this rate, and except in times of major enemy offensives such as the Battle of Britain, defensive patrols were usually safer still. Not surprisingly the highest loss rates of all were sustained by Japanese Kamikaze missions, but conventional Japanese attacks on American ships late in the war came close, often sustaining 25% or greater loss rates,

The non-combat risk. Some types of mission carry substantial risks aside from enemy guns. Flying at night was inherently dangerous: German night fighter forces defending Germany lost far more aircraft to accidents than to British guns. And small planes operating from carriers ran a high risk of navigational error causing them to run out of fuel before locating their ships.

Tempo of operations. Here we show the loss rate per month, but a key factor in this rate was the number of operational sorties flown each month. Strategic bombers might fly only one or two sorties per week, while fighters defending against them often flew several sorties per day. Carrier aircraft typically flew fewer sorties than their land-based equivalents. And air arms with low serviceability also flew fewer sorties.

Training. Aircrew experience turned out to be a major factor in aircraft loss rates. For example, an RAF bomber command crew had a 10% chance of being shot down on their first mission. If they survived long enough, by their 20th mission this chance had dropped closer to 1%. In the later stages of the war both German and, above all, Japanese aircrews went into action with greatly reduced training, and suffered correspondingly greater loss rates.

These losses in aircraft came with a commensurate toll in human life. Aircrew casualties amounted to about 346,000 men killed or missing on operations. While the total number of aircrew killed is much smaller than the number of infantrymen to meet a similar fate, the only group of combattants to suffer loss rates at a higher level than aircrews was submarine crews.

The ratio of aircraft lost to aircrew lost depends on two factors. One is the size of the crew carried by the aircraft shot down. Average crew sizes were larger for the Western Allies because of the large contributions of strategic bombers to the loss totals. The other was the proportion of aircrew that survived. For the Germans and Western Allies, aircrew losses amounted to about two thirds of those on board (including some who were killed even though their aircraft survived.) Russian and, in particular Japanese aircrews, had a lower survival rate. All air arms saw many cases of pressing combat to certain death rather than disengaging, but the Russians and, above all the Japanese, carried this approach further than the Germans or the Western Allies.