whatever it is a woman with small boobs can do much? What can a pair of nipples do?
Air defense in the event of war with the one or more neighbours will not be limited to just flying circles over 710sq km.
One of the first tasks at hand will be to neutralise the air power of the enemy. Once that is achieved Singapore will then be able to patrol the sea lanes unhindered to prevent a blockade of any sort.
You have to understand that a large part of Singapore's defense involves offense. We can't just sit back and allow artillery and missiles to rain down on the Island. Defense in depth will have to be achieved.