System Startup slow when Airport enabled.


I have a PowerBook G4 running OS 10.3.9 – when I boot up the system with Airport still enabled, it can take a long time (10 – 15 mins) before the system starts up. Is this normal??? The laptop basically connects to two different Wireless networks – one at school and the other at home. Normally I disable Airport before shutting down – then the laptop starts up quickly, but if I forget, I have to pay the price on startup… Is there a setting I should check??? Is there a way to automatically disable Airport on system shutdown???