She may work for United Airlines. We don't say she "serves" for them. The sentence She works for Microsoft tells you which company employs her but says nothing about where her office is. If you want to know her location, you need more text as in She works at Microsoft headquarters in Washington.
Her father serves at the airbase could be correct if her father is a member of the military but it's not very natural. Works would be better. He serves for the air force (no hyphen) is incorrect.
Interested in Language