And something as powerful looking as that bombardment weapon is is going to impose a lot of structural stress on an unprepared area. The bay can be filled with cargo containers too but it'd be a little weird looking. Yeah I've heard about the ballistic missile launch tests - but my point is more that that's not what the area is designed for. That's the case with any pretty much any scifi big hangar system I can remember - no equivalent to touch and go.

Though I think if a fighter is lining up on a hangar, once they get past the lip of the main bay they have the same fighter lengths available for final approach than a carrier fighter hitting a deck just because the bay is so damn big and a TIE is so damn small - but if the system somehow misses the 'catch' the fighter goes splat. Landing *is* awkward, since a fighter has to get up into the bay volume then level out. Unless flank apertures are huge any recovery is probably going to have to be automated with tractor beams anyway. So that's almost like the apertures you're talking about. I think for launch at least the the sides of the main bay are all launch racks bays, just behind doors. Really these ships should just have torpedo tube like apertures a few places that let the fighters come in an out, but graphic designers didn't allow that long before the authors got involved. It's not unreasonable to think that some ships might be modified to exploit that space, that seems to be a leftover legacy of even worse designed clone wars era ships, for some other purpose. The fact is nearly every single one of the Star Wars shipboard hangers in a horrible inefficient waste of space, and the ISD ones are bonus stupid since they don't even simplify takeoff and landings while the ship is underway.

Another option was to strap the MX to the side of the CVN island and drop them from that position. The US did a whole test series of firing V-2 rockets off carrier decks, plus I have an official diagram around of how an MX missile on a motorized trolley can be driven off a Nimitz class hanger deck to fire from the water.

Star wars orbital bombardment