"
B-29 raids in PTO were about the only ones to flew above 30K and even they switched later to more reasonable alts.
"Gen. Thomas Power, Commander of the 314th Bombardment Wing, carried out a fire raid test over Tokyo. Bombs were dropped from 25,000 ft. and burned out a full square mile. He reported to LeMay that he thought by going in at lower altitude with a larger bomb load there would have been much greater destruction.Then came the radical decision by LeMay. The planes would go in at 10,000 ft. He ordered the removal of bomb bay fuel tanks claiming by not going to altitude they would not need the gas. All .50 cal. Guns would be removed, and all ammo. With no guns the gunners did not need to go."
"On March 9, 334 B-29s took off from Guam, arriving in Japan under good weather conditions. The planes were stacked up from 4,900 ft. to 9,200 ft. "
"For three hour the B-29s kept coming. Only a few fighters appeared causing little damage. We lost 14 planes with damage to 42. An official Japanese count reported nearly 84,000 killed, 41,000 injured, and over 250,000 buildings destroyed in this one raid. 16 square miles burned out."
Source of these quotes Plenty more sources available but my interest was raised in this when the same information was given on the History Channel. Note: All these low raids were at night.
If you worry about B17 firepower at high alts then:
"On January 27, 1945, the B-29 identified as "B-29 A Square 52" scored 14 kills over Tokyo, Japan, as follows: rammed by two fighters, gunners then shot down 12 more fighters, the damaged bomber flew 1,500 miles back to Saipan on three engines, crash landed, all crewmen survived, but the aircraft was written off. This is probably the highest number of air-to-air kills by a single airplane during one mission."
Source
