How does grease become airborne?
Let's reword it:


Traces of oil and grease are distilled off at temperatures below their boiling points. 
The temperature in the frying pan is above 100 °C.
The food does contain significant amounts of water.


This sounds like the conditions for steam distillation, except that you're collecting the mixture of water and water-insoluble material everywhere in the kitchen and not in a flask.