@ John and Richard Simpson

I have to add my 2 cents.

Orwell was technically correct...enough AA would keep bombers from being effective for a few reasons. The first (and more myopic) is that enough AA would cause so much havoc with the bomber formations that Germany would not have been able to field an effective flight of aircraft if, say, they were losing 50-100 craft and crews at a throw. Technically true, but then how much AA would be enough to effect this result? Obviously, more than Britain had in its standing defense force, and even that was probably less than a 1/10 of what would be necessary to bring those kind of numbers about. England would have had to have been encrusted with AA from the coast to the middle of strategic population centers such that inbound aircraft would be getting hammered all the way in and all the way out.

As it was, there was a fair amount of artillery, but located in concentrations relatively close to the cities they were defending. The standing Air Corps had to take up the slack with very few aircraft relative to the early German inbound filghts. Thus, Germany sends planes in, but are losing too few to justify suspending operations, continuing a bombing campaign for several years. That is parts of the economics of warfare that Orwell apparently didn't reconcile.

As far as service ceilings, you are technically correct. The problem was that aircrews typically flew far below those ceilings for several reasons. German aircraft, good as they were, were usually designed as multirole aircraft. As such, few were actually flown below their optimum configuration. Plus, in the case of Germany, they relied primarily on twin engined aircraft which are very subject to the laws of ballistics and smaller in bombload, thus needing far more aircraft to do the same job of a Lancaster or B-17 detachment. Had Hitler approved construction of high-altitude heavies early on, things could have been a whole lot worse (if one could even imagine that) for the inhabitants of Britain.

All that aside, the primary reason that aircraft operated below the threshold that would have put them out of reach of flak (and most fighters) was that although the Norden bombsight and others could calc the physics of falling bodies at any altitude/speed...the bombs had troubles hitting home even at 10-15 thousand feet. The reason was not known until after WWII. The physics of falling bodies was tight, but those in know had no idea that the "jet stream" existed, much less that winds often change direction significantly every 5-10 thousand feet. In fact, the Lancastrian that smacked the mountains in Chile in 1948 (maybe Peru), the aircrew flew in on-off poor visibilty and ended up plotting course by compass and airspeed. They knew they had the altitude, however when they plotted for calc airspeed, the came up 100+ miles short and started their descent straight into the mountains they thought that they had flown over. What they didn't know was they were flying into a severe headwind caused by the jet stream.

High altitude bombing was considered the best bet early on in the war, but was wildly ineffective even with huge formations. I have read several accounts where the accuracy of bombing campaigns was calculated as low as 8% and and "high" as 25% on good days. Actual effects on the bombs were not calculated as they fell towards earth simply because no-one knew there were effects to be calculated outside the physics of the blackboard. To sum up, when accuracy had to be maintained, the operation ceiling of the group generally lowered. Because of the inherent problems of getting it in the pickle barrel, you have huge formations to carpet bomb high value targets instead of a few super-accurate bomb strikes made by a few aircraft. As such, one can see why '17s, '24s and Lancs were getting plinked throughout the war. Even the Superfortresses during WWII and Korea were suffering the same fates (much of it was due to the plane itself) though they were constructed to fly very high and very fast out of the reach of everything...but their bombs hit targets more out of pure luck at those heights than for any other reason.

I'll shut up now. Just had to throw my 2 cents in. I should keep those pennies though....they are becoming more valuable for their metal compostion than their face value.