The 'network' line in the kickstart file will determine the network configuration during and after installation, but if you don't provide all the information for a static configuration the install will use dhcp. You can override the kickstart configuration by providing arguments to anaconda in the boot options, for example the following will perform the inastallation with a static address :-
linux ksdevice=eth0 ip=x.x.x.x netmask=x.x.x.x gateway=x.x.x.x dns=x.x.x.x ks=http://...
.. even if I have this in my kickstart:
network --bootproto dhcp
You have to find the right balance between flexibility and automation, also please keep in mind that kickstart options are always changing/improving so you should read the doco matching your installation version.