In this update, a couple of small adjustments and new features:
press and hold the 'cap' button to lower the skill value (reduce traffic), and holding it till 4.0 now closes the airspace entirely
more accurate heading suggestions from planes near storms
adjusted altitude of inbound aircraft, so they don't enter higher than the top of the airspace anymore
text at the bottom of the screen shows the distance d between the selected plane and the current cursor position
adjusted some initial headings after takeoff
planes to secondary airports now reduce to speed 220KT automatically, similar to planes inbound the main airport
planes inbound KJFK no longer initially fly inbound the LGA VOR, to avoid possible confusion with traffic actually having KLGA as destination (which have an LG tag)