Board Thread:Warhammer 40k General Discussion/@comment-203.134.114.240-20130706042929/@comment-3258762-20130715165956

The Energy Shield would not defend at all against biological weaponry, because if it doesn't let bacteria in, it would be like fighting in the vacuum of space, which no matter the suit is quite annoying (Which we see early on in Halo 4) and since the Spartans do not seem to be moving faster and they seem to be able to hear the surroundings, it means air passes into their shields, meaning bacteria passes through it.

As for the airforce: I am not too educate in the Imperiums airforce other than it follows the same standard as most of their normal forces: Strength in numbers. So I cannot answer that.