Editing Operation Downfall (section)

===Air threat===
US military intelligence initially estimated the number of Japanese aircraft to be around 2,500.{{sfn|Frank|p=206}} The Okinawa experience was bad for the US—almost two fatalities and a similar number wounded per [[sortie]]—and Kyūshū was likely to be worse. To attack the ships off Okinawa, Japanese planes had to fly long distances over open water; to attack the ships off Kyūshū, they could fly overland and then short distances out to the landing fleets. Gradually, intelligence learned that the Japanese were devoting all their aircraft to the ''kamikaze'' mission and taking effective measures to conserve them until the battle. An Army estimate in May was 3,391 planes; in June, 4,862; in August, 5,911. A July Navy estimate, abandoning any distinction between training and combat aircraft, was 8,750; in August, 10,290.{{sfn|Frank|pp= 209–10}} By the time the war ended, the Japanese actually possessed some 12,700 aircraft in the Home Islands, roughly half ''kamikazes''.{{sfn|Giangreco|2009|p=xviii}} ''Ketsu'' plans for Kyushu envisioned committing nearly 9,000 aircraft according to the following sequence:<ref>JM-85 pp. 18–21</ref>

* 140 reconnaissance planes to detect the approach of the Allied fleet.
* 330 Navy bombers flown by highly trained pilots to attack the Allied carrier task force to prevent it from supporting the invasion convoys.
* 50 "land attack planes," 50 seaplane bombers, and 50 torpedo bombers flown by highly trained pilots for night attacks on convoy escorts.
* 825 Navy ''kamikazes'' to attack the landing convoys prior to their arrival off Kyūshū.
* 2,500 Army aircraft (conventional as well as suicide), together with 2,900 Naval trainers for ''kamikaze'' attacks against the landing fleet as it arrived and anchored (5,400 total).
* 2,000 Army and Navy "air superiority" fighters to escort the ''kamikazes'' and strafe landing ships.
* 100 transport planes carrying 1,200 commandos for a raid on the US airbases on Okinawa, following the success of earlier smaller-scale operations.

The Japanese planned to commit the majority of their air forces to action within 10 days after the Allied fleet's arrival off Kyūshū. They hoped that at least 15 to 20% (or even up to a half) of the US transport ships would be destroyed before disembarkation.<ref name="OLYMPIC VS KETSU-GO">{{Cite web |title=OLYMPIC VS KETSU-GO |url=http://www.ibiblio.org/pha/war.term/olympic.html |access-date=February 24, 2023 |website=www.ibiblio.org}}</ref> The United States Strategic Bombing Survey subsequently estimated that if the Japanese managed 5,000 ''kamikaze'' sorties, they could have sunk around 90 ships and damaged another 900, roughly triple the Navy's losses at Okinawa.<ref name=":0">{{Cite web |title=USSBS Report 62, Military Analysis Division, Japanese Air Power {{!}} PDF p. 25|url=https://www.scribd.com/document/50311346/USSBS-Report-62-Military-Analysis-Division-Japanese-Air-Power |access-date=February 24, 2023 |website=Scribd |language=en}}</ref>

Allied counter-''kamikaze'' preparations were known as the [[Big Blue Blanket]]. This involved adding more fighter squadrons to the carriers in place of [[Torpedo bomber|torpedo]] and [[dive bomber]]s, and converting [[Boeing B-17 Flying Fortress|B-17s]] into airborne [[radar picket]]s in a manner similar to present-day [[Airborne Early Warning and Control|AWACS]]. Nimitz planned a pre-invasion feint, sending a fleet to the invasion beaches a couple of weeks before the real invasion, to lure out the Japanese on their one-way flights, who would then find ships bristling with anti-aircraft guns instead of the valuable, vulnerable transports.{{citation needed|date = July 2014}}

The main defense against Japanese air attacks would have come from the massive fighter forces being assembled in the [[Ryukyu Islands]]. The US Army Fifth and Seventh Air Forces and US Marine air units had moved into the islands immediately after the invasion, and air strength had been increasing in preparation for the all-out assault on Japan. In preparation for the invasion, an air campaign against Japanese airfields and transportation arteries had commenced before the Japanese surrender.{{citation needed|date = July 2014}}