I kept both roof hatches, in the summer when I really don't need air I just pop them up and open my side windows and they create an up draft and the heated air goes out. For roof top air units I framed in new openings for two units one in front one in bedroom. On the roof hatches I have a screened door that drops down to open and close them and to keep bugs out, also provides fresh air at night in cooler days.
