The idea behind daylight raids was that bombers were more accurate when they could actually see targets so the damage inflicted would be concentrated more so that a night time carpet bombing.*

All of the footage I see, including CGI in movies, depicts large formations of US bombers giving the impression that the "precision" raids were anything but precision.

What was the "footprint" of an average American daylight raid? If you had to draw a 2D box on a map, what values would you assign to length and width?

*Not saying that it was done to protect civilians, clearly the objective was to destroy strategic targets.

  • 2
    $\begingroup$ Footprint meaning the size of the aircraft formation, or the dimensions of the bombed area? $\endgroup$
    – Ron Beyer
    Jan 28, 2017 at 2:12
  • $\begingroup$ Interesting. I assumed they would roughly match since winds aloft would have similar effects on each individual bomb. If I have to choose, I'm more interested in the formation itself. That said, it would be interesting to compare both. $\endgroup$
    – acpilot
    Jan 28, 2017 at 2:16
  • 1
    $\begingroup$ Not necessarily, it might if they all dropped at the same time, but they usually have specific targets so at the very least it would be as wide as the formation, but doesn't have to be very long. $\endgroup$
    – Ron Beyer
    Jan 28, 2017 at 2:25
  • $\begingroup$ Right, the idea being to land bombs on a specific target. $\endgroup$
    – acpilot
    Jan 28, 2017 at 2:46
  • 1
    $\begingroup$ Aside from a few specialised squadrons and weapons, there was no such thing as precision bombing in WWII. Googling will quickly find statistics but I seem to recall that there was less than a 1% chance that a bomb would fall on target (within 1000 feet). Most factories either did not stop production or were back online within a day or so. There was a raid on a Japanese plant with hundreds of bombers that put a single bomb on target. I would say that "many square miles" is probably as good an answer as you could get. $\endgroup$
    – Simon
    Jan 28, 2017 at 8:54

2 Answers 2


The size of the bomber formations (bombers streams) varied significantly depending on the number of bombers , the time , location and other things. The most common figure quoted figure is around 70 miles long and 5-6 miles wide (for ~500-600 bombers). However, the formation's footprint depended on a number of factors ranging from the navigator's skill to the wind in that area.

The figures vary wildly. For example, from the book Mission to Berlin: The American Airmen Who Struck the Heart of Hitler's Reich:

The stream of more than one thousand Eighth Air Force bombers, from one end to another was 360 miles long. ... on ... February 3, 1945, when the first flying fortresses reached Berlin, the last bomber was over the Zuiderzee in Holland.

This extreme length is a consequence of the situation late in the war, where allied air armada roamed European skies without bothering much about the Luftwaffe. The time spent over the target, on the other hand was quite small-

... each Fortress crew would spend only between thirty and sixty seconds over the center of Berlin itself...

Note that there was no such thing as precision bombing in WWII (except for some special cases), though the accuracy did improve over the war. Of course, some of this was due to the way the 'target' was designated- anywhere 1000' of the aiming point was good enough. From The United States Strategic Bombing Survey:

Conventionally the air forces designated as "the target area" a circle having a radius of 1000 feet around the aiming point of attack. While accuracy improved during the war, Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area. A peak accuracy of 70% was reached for the month of February 1945.

Accuracy of RAF night bombing improved from ~20% in 1942 to > 90% in 1945. Of course, the British target was comparatively larger- anything within a 3 miles radius of the aiming point was a 'hit'.


enter image description here
By Anynobody [GFDL or CC BY-SA 3.0], via Wikimedia Commons

Combat box of a 12-plane B-17 squadron developed in October 1943. Three such boxes completed a 36-plane group box.

The formation is called a combat box.

The Combat Box was a tactical formation used by heavy (strategic) bombers of the U.S. Army Air Forces during World War II. The combat box was also referred to as a "staggered formation". Its defensive purpose was in massing the firepower of the bombers' guns, while offensively it concentrated the release of bombs on a target.

Different formations were tested and used, giving different sizes. It also depended on the type of aircraft as the different handling characteristics affected the dimensions/spread of the box, so there isn't one definitive size I can refer to, however the Wikipedia article linked above lists their evolution and variation by type.

One such example used by the B-24 was a—

... line formation that was 2,440 ft (740 m) wide and 700 ft (210 m) vertically, but only 320 ft (98 m) deep, reducing the time over target significantly.

The article lacks consistency in the terminology used, so I'm not sure what is meant by deep.

  • $\begingroup$ In the last quote I'm pretty sure "deep" is the distance between first and last aircraft in direction of travel - it notes vertical height seperately. This would match with reducing time over target, as it would be a thin line passing over rather than a larger spread. $\endgroup$
    – Andrew
    Jan 28, 2017 at 17:29

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