Its by and large a Doctrinal thing methinks. Nations who put greater stock in their armies will work to develop more powerful anti-air batteries. Nations with powerful air fleets probably have dedicated interceptors for smaller craft (think flying gunboats, which going off of that I could see Boerd's rocket barges filling a similar role to Torpedo boats of the air if they swap for fewer and larger rockets depending on who they're firing upon) and can also simply force a fight in the sky against their own air fleet.