How do you guys handle infantry defense? Defending against enemy aircraft goes without saying but mission planes usually have phosphorous rounds or bombs supposedly for the enemy troops attacking across no-mans land. However, I have yet to see any attacking troops. Letting the AI fly the planes and they would not attack ground targets (I learn what one should do on a mission by letting the AI fly it).
As far as balloon defense, these missions are terribly undermanned with two planes usually going after 5-9 enemy scouts. Is there some sort of method in this madness? When in command of the flight, I tend to take the failed mission and once the balloon is destroyed (which will happen anyway), go off on a patrol of sorts hoping a few bomber kills will raise the negative score. Any insight on this?

Didn't realize there were differences of that sort - I wondered why the manual showed all these never seen infantry troops. I've gotten the mission from time to time, maybe four times in 1.7 campaigns. Seems to happen relatively a lot to the Germans late in the war when they are flying as many as four missions daily. Probably just because of the greater number of missions, the random chance is higher. Again, though, I'm using HASP and you are not so that might be the difference.
As per balloon defense, then the object is to get their attention well before the balloon then run like the devil hoping they follow?

What ever it takes to protect the balloon and to lose no one in your flight. With that you will earn points. Take some of them down and it is all good.

Prior to my 'let the balloon burn" plan, I flew high in the opposite direction they were going then dove on the last one. Gave me a fair initial advantage but the balloon was toast and my idiot wingmates generally took their time joining me. When I duke it out with such large numbers, my wingmate is usually toast pretty quick but I have noticed that if the player flies low, wingmates follow and the AI doesn't seem to handle low flight very well (understandable - you don't know how many times I crashed and burned going after fleeing enemy flyers). Seems the allies early planes and Camels like to fly into the ground in dog fights. That is usually the only way I get a "kill" in those uneven fights it seems. They just follow when flying low and an occasional sharp turn gives one additional flee time. Funny, seems their named aces will follow you all the way to your base - by themselves (happens when I run out of ammo).

And then slaughter your whole, entire squadron as they go into landing pattern from a mission. Has happened to me

Sounds like a job for CM11 :)

Actually I think in the end it became a job for the recruiters. :)