Krieghund, thanks for coming to my defense. I must apologize for not being more careful. However, I am very often accused of being tiresome when I spell out every single thought necessary to make my point. Although, it appears in my haste to edit my own post, I made a mistake. I fear that if I make the whole of my case I will be considered tiresome. So, in brief let me say …
Yes my main point is that with fighters, bombers enjoy a special one-third protection in general. With small numbers of aircraft, which would most likely be used against only small numbers of AA dice, the benefit is often even better. In my example with one fighter and one bomber, against one die, the bomber is of course immune to AA. Against two AA dice, the bomber is only at risk 11.1% of the time. Against three AA dice, the bomber is only at risk 7/27 of the time, still less than one-third. Against four dice the odds put the bomber at risk 33/81 of the time, which is now slightly more than one-third. Against five dice, the odds for the bomber drop quickly because now the bomber has a direct chance of getting stung by the fifth die. And six dice is only worse. But regardless of the number of dice, the chances of a bomber getting whacked drops substantially, even if you add only one fighter. More fighters only makes things better.
My point is that fighters clearly improve the effectiveness of bombers to deliver damage on the enemy. In general, the battle box indicates this to be a drop to about one-third the chances of getting eaten by AA, but specific numbers of attack dice and fighter escorts will have some effect on the real odds in a particular battle.
I recognize the names of the folks in this thread as notable contributors to the forum. I hope I have not given offense while defending my thesis on the merits of using fighters in conjunction with bombers.
edit: After reading the questioned post, I feel I was clearer than I was credited. I did state, and was later highlighted in italics, that you need to kill the fighter first when rolling less than five dice. This is exactly what others went on to illustrate in their challenges, that two hits would kill the bomber, which is what I said in my own words.