No, anti air is not good at all, and this has been a running theme in the Hearts of Iron series. The devs should at least give AA some piercing/ hard attack capability to simulate how they were sometimes used as anti tank weapons like for example the mighty flak eighty eight. mobile AA like M15 half track should also have soft attack and some piercing and hard attack. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.