So long as you don't justify it with a modern day naval carrier, I have no quiblles with the 120-ship figure for the Orion, etc. If you had been referring to an FS2 340m long ship having 80 fighters, that would be complete and utter bollocks, of course.
(But that doesn't imply it is possible to simply strip down a ships turrets in order to fit more fighters in)
Actually, if you look at the length, it gets interesting
120 25m long ships (minimal size, really too small for a good estimate) would require 3000m length of ship. Far too big, especially if you look at where the Aquitane fighterbay is (it's likely to be the same area where the bulk of supplies and fighters are kept, for logistical reasons).
In a 1000m space, assuming 20m wide vessels (ignoring spaces), you could fit 50. With seperation, and structure, you;re probably looking at 20-25. Which means, in reality, you could proably stack, pack & rack 'em in the space the Hecate has in its front nose
So.... if you look at it, it actually fits in quite well in terms of fighter volume.