@Fighter212:
does anyone know if navel and air bases can be destroyed.
They cannot be destroyed. However, they can be strategically bombed and damaged.
If a naval or airbase is strategically bombed for a value of 3 or more, the base is considered to be non-opperational (up to a total damage of 6). However, the owner of the base may pay at the puchasing phase of their turn to pay-off damage on the bases to make them opperational. This system works just like the strategic bombing of industrial complexes in all current versions of the game.
Thus, you still need to defend your bases.