Indeed they did! 30,000 fighters in a 2.4 km x 0.8 km x .4 km ship is too freaking much.
Even the Super Star destroyer with its 17 kilometers in length can only carries 1,728 fighters combined with it's planetary Garrison equivalent of troops, armor, and even pre-fabricated base materials.
This is mainly because you have to consider support equipment to maintain craft, crew quarters, pilot/marine quarters, recreation facilities, engineering, ship-vital equipment, and the humongous list of areas a ship needs. I don't care if they use something equivalent to the Nodal system...the sheer volume of the carrier is too small to support that many.