I considered using a modified proposal, but fuel pod and rocket pod really are quite different. And the airship fighter isn't really the same thing as the ground-based fighters.
Interceptors need guns more than fighters. The interceptor is based around the principal of quickly reaching a target and quickly destroying it, ideally the interceptor will take down another aeroplane in a single pass and be gone before anyone can retaliate. The fighter is designed to avoid damage and close range, then keep in range while it acquires an effective hit. It will need to will want to turn faster than whatever it is chasing, it can afford to be a bit slower because whatever it is chasing can either try to avoid fire, and slow down as a result, or run away in a straight line and be an easy target. The interceptor needs to do a lot of damage in a single pass, the fighter can afford to wait until it has a good shot. Extra guns help, but manoeuvrability helps more, and increasing the momentum of the wings in not going to do much to help that. Of course, there is the issue of being able to aim being rather difficult in a plane, so having lots of guns spread out is not all bad, but I suspect that varied calibres will confuse aiming and excessive guns will reduce turning. Interceptors are for attacking things that don't want a fight, fighters are for attacking things that do...
Well, we have the engines, but more is better right, and this should improve other altitude affected systems, such as the pilot, and the lift surfaces, and the fuel tanks, and pretty much everything really...
Replacing factories keeps folk busy and losing factories makes folk permanently not busy. Getting our civilians fortified is a nice bit of preparation that could see us gain some significant savings in the long-run. Also, covering our nation in bunkers is just cool...