many different terms for the same thing. air screw, pilot screw, slow adjustment, etc. as a rule of thumb, if the screw is on the airbox side, its an air screw. turning this screw in reduces the amount of air and richens the slow speed circuit. if the screw is on the engine side of the carb, its referred to as a fuel screw but often times still called the pilot screw.
on your carbs, both sleds, your adjusting the air intake at low speed. turning the screw in reduces the amount of air(richens), out increases air(leans). the air jet your referring to is located in the opening of the carb on the airbox side. there are 2 or three holes if you look, and the air jet is usually at 5:30 or 6:00 position. very tiny opening in this and its easily plugged often times creating the issue your having and often overlooked when cleaning carbs. if its blocked or partially blocked, the air screw will have minimal to no effect when adjusting. these air jets are available in different sizes, thats why yours is noted as .5. rarely are these changed except for serious tuning most times in race applications.
to answer your question, if you turn the pilot, air, slow adjustment screw in, your blocking the air jet, reducing the amount of air and richening the low speed circuit. by turning the screw out, your opening this circuit increasing the air flow thus leaning the circuit.
rich=more fuel, lean=more air.
hope that helps a bit to clear the confusion. more info available if needed.