Defeat in detail, or divide and conquer, is a military tactic of bringing a large portion of one's own force to bear on small enemy units in sequence, rather than engaging the bulk of the enemy force all at once.
This exposes one's own units to many small risks but allows for the eventual destruction of an entire enemy force.
An overwhelming attack on one defending subunit minimizes casualties on the attacking side and can be repeated a number of times against the defending subunits until all are eliminated.
An attacker can successfully conduct the tactic of defeat in detail by exploiting the absolute weaknesses or comparative disadvantages in the deployment or structure of defending troops, as well as advantages such as maneuvering speed that the defender cannot match.
Thus, if a unit is equally suited for use against cavalry and aircraft, using it to eliminate enemy aircraft would have benefits that would last well into future engagements against enemy cavalry units weakened by their lack of support.