The Japanese are saving their fuel and husbanding their aircraft to throw everything they have against the invasion.
The aircraft have also been dispersed away from the main airfields and are being camoflaged out in the country in woods, between farmhouses, etc... With the lack of fuel, disruption of command and control, and a staggering American aerial dominance, you have to wonder whether the Japanese were going to be able to mount any sort of coordinated strike on the invasion forces.
It's also interesting that at least one Tokyo newspaper feels it can publicly criticize the Army militarists who have led Japan to disaster. And they don't know the half of it yet.