Counter-intuitively, the advanced nature of the B-29 was one of the main overarching factors that precluded its use in the ETO. There were several overlapping reasons why the B-29 was never deployed to the ETO and the leading edge technology of Boeing's plane threaded through all of them.

The decision to deploy certain weapon systems often have a political component, and in the B-29 was no different in this respect. The "Europe First" strategy rankled a number in the Navy and for MacArthur's Army generals who felt they had to accomplish more with less modern equipment. In this sense, earmarking the B-29 for the war against Japan was a sop to this grumbling by assuring that America's most advanced bomber would soon be assigned to there. FDR too saw the assignment of such a heavy bomber as beneficial to the inner-Allied relationship. FDR had broached the idea of deploying the B-29 to the CBI during the Casablanca conference as a way to stiffen up Chinese morale and hurt the Japanese in East Asia. Of course, such a commitment would have also necessitated both British and Chinese to step up their efforts within the CBI theater to keep the B-29 campaign afloat. So the B-29 would not only smash Japanese defenses, it would also force a greater commitment by America's allies in the region.

Commanding General of the U.S. Army Air Forces General Henry Arnold did not particularly relish the idea of using the B-29 in the CBI. While Arnold pushed for the B-29 monopoly in Asia, he did not want to diffuse the bomber in distant secondary theaters away from the public eye. Arnold had to fight against MacArthur's air chief, General George Kenney, who wanted the B-29 for use in complementing MacArthur's drive across the SW Pacific. This would have been problematic for Arnold's long-range goals in that he envisioned the best use of the B-29 to be in the Marianas. While Arnold's position had tactical merit, it also served the wider interests of both the USAAF and strategic bombing in general. If the B-29 could deal a clear knock-out blow against a "virgin" target like the Home Islands independent of any other service's efforts, then it would both justify the doctrine of strategic bombing and the costly B-29 program. The Superfortress was one of the most expensive military programs of the US war effort and there were some Congressional investigations into cost-overruns and delays for the aircraft.Such critiques were not limited to Congress as there were some voices in the USAAF calling for the program's cancellation. Having the bomber perform a decisive campaign on its own in a visible theater like the Central Pacific would vindicate Arnold's defense of the program while the plane was under development.

Logistical needs also reinforced Arnold's partisanship of the Marianas basing. He had already expressed doubts as to the viability of the CBI option and experience in China showed these doubts to be correct. The B-29 was a very large and technically-advanced bomber, and to have a B-29 deployed in a theater necessitated a logistical tail. This was one of the reasons why there were few 8th AF heads calling for the B-29. The UK already had a large number of B-17 and B-24 for its missions, and adding a third bomber to the mix would have created its own shares of logistical headaches. Added to this, the existing airbases in the UK in 1943/44 would not have been amenable to B-29 operations. The B-29's landing and takeoff weights would have put pressure on the runways in the UK; while they could handle the lighter heavies, these runways lacked the reinforcement for sustained operations of a heavier aircraft. This problem came to the fore during the postwar Berlin Crisis in 1948 when the USAF Silverplate deployment found that UK airbases lacked dispersed hardstands suitable for a B-29 and the aerodrome infrastructure was inadequate for sustained operations. One advantage of using the B-29 in the Marianas was that the Army Corps of Engineers could construct runways from scratch to incorporate prior lessons in airbase construction for this advanced heavy bomber.

Finally, and perhaps most importantly, the B-29 could fulfill the bombing role in the Pacific in ways that the other American heavy bombers could not. The greater range of the B-29 meant that it could bomb the Home Islands from bases in China or the Central Pacific. The timing of the decision to deploy the B-29 in Asia- ca. 1943- meant that these would-be airbases were either already under Allied control or would soon be brought under Allied power within a year to eighteen months. To rely upon the older warhorses of the B-24 and B-17 would have meant the bombing of the Home Islands would come much later, likely 1945, as they would need airbases closer to Japan. In contrast, most of the German sphere of influence was accessible to the 8th or 9th AF by this time. The B-29 might have done the job better than its predecessors in the ETO, but not deploying the B-29 to the ETO was not a precondition for a bombing campaign. The Liberators and Flying Fortresses were handling the job quite well by this point. The same could not be said for the Pacific where the range of the B-29 was the difference between having a strategic bombing campaign in 1944 and having to wait at least another year before the Allied power could reach the Okinawas and the Bonins.

Sources

Leary, William M. We Shall Return!: MacArthur's Commanders and the Defeat of Japan, 1942-1945. Lexington, Kentucky: University Press of Kentucky, 2004.

Wolf, William. Boeing B-29 Superfortress: The Ultimate Look: from Drawing Board to VJ-Day. Atglen: Schiffer Pub, 2005.

Wolk, Herman S. Cataclysm: General Hap Arnold and the Defeat of Japan. Denton, Tex: University of North Texas Press, 2010.

Thanks for such good responses. The placating of MacArthur's generals is an aspect of the war, I've never come across in my readings