Looking at Clan culture, they considered the ability to secure air supremacy important enough to A) include Aerofighter pilots in the ranks of the warrior caste, bloodnames and all and B) subject them to the full gamut of Clan eugenics procedures (even if the results are... spotty), but at the same time many stories of Clan warfare have the air units bid out, dropships granted safe passage, and generally remove them from making a decisive contribution to a conflict. Sarna goes so far as to note in the article on zellbrigen that the aerofighters didn't even have fully codified dueling rules until after the invasion of the Inner Sphere started.

So, hypothetically speaking, say there's a clan fight about to happen, the batchall is issued, everything gets bargained and well-met, and it works out to each side having a full star of aerospace assets on top of the ground units duking it out. Presumably both of these forces meet in the air and go at it one-on-one until one side is shot down or quits the field... but then what happens? An IS air unit would happily take advantage of air supremacy to hassle enemy units and logistics, but what do Clan fighters do with all that free space? Is blowing up enemy supply dumps and coolant trucks (assuming they weren't explicitly agreed to be out of bounds) good tactics or dirty pool? Is an enemy mech between 1-on-1 fights fair game? Or are they just expected to fly back to the dropship, crack open a metaphorical cold one, and wait for the mechwarriors to decide the real winner?