Calculate a baseball player's batting average. Calculating a baseball player's batting average is not a difficult task at all. A batting average represents the percentage of at bats that result in hits for a particular baseball player. The formula is: That's all there is to it.
To fly under the radar means to act in a way so as to actively avoid detection. It is the opposite of 'in your face'. There is an element of getting away with something but it is not necessarily bad.
Airspace[1] is the portion of the atmosphere controlled by a country above its territory, including its territorial waters or, more generally, any specific three-dimensional portion of the atmosphere. It is not the same as aerospace, which is the general term for Earth's atmosphere and the outer space in its vicinity.