I wouldn't put too much faith into those sizes.
All those are just estimates, even on the stuff that have TT models in 28mm scale, let alone BFG scale. Furies and Starhawks having no large-scale models fall into the wild speculation category.
I wouldn't trust the word of authors on that, either;
Gordon Renie in his book, "Execution Hour" estimates an Imperial cruiser is 3 km long, and a Starhawk weighs 200 tons, and two such craft can launch simultaneously from a single launch ramp. .... I mean, it's a good read but that detail doesn't sound right.
Well, at 3000m total length (incl. ramming spike) for the vessel, that entire ordnance bay segment would be at best 550 meters long, rounded up. Divide by 4, because there are 2 rows of 4 launch ramps, you get 137.5 meters. Divide by 2 because each of them ends in a triangle, with one face being the side wall and the other houses the bay door, that's 68.75 meters each face. Multiply by 1.43 because it's diagonal, and as such a bit longer than if it was parallel with the main hull, that's 98.3... meters. If you look really closely on the model, you'll see the actual door itself is in the center 1/3rd of that face; Divide by 3, and we're finally told that the baydoor is roughly 33 meters wide.
How large a craft would you fly through that? Taking off couldn't be that hard if it's via launch rail, but how about landing? Sending a craft with even half as much wingspan through an opening is a mean feat by itself, and probably suicidal if we count for drift, and the mothership's movement.
I've only seen mentions of these crafts lengths, not wingspans, but I highly doubt they'd be 100 meter long and 16 meter wide darts.
Most imperial aircraft has about as much wingspan as their length, if not more. The Fury and the Starhawk are said to be dedicated voidcraft, but said book, and "Warriors of Ultramar" mention they can be outfitted for atmospheric flight, so maybe, half as much wingspan?
It takes an ork, and probably good 'ol Killboy at that, to fly a 50 meter broad craft through a 33 meter hole.
Of course that 3 km size estimate for the cruiser is way too small. Some say it's 5, others say it's 8; They'd have roughly 55 or 88 meter wide baydoors respectively, which still sounds way too narrow, and there's no guarantee that wingspan is really just 50 meters.
.... And, we're still supposed to launch 2, side by side, at least according to Renie, which, if I'm not mistaken contradicts the game rules, because I'm fairly certain I've never seen a Dictator launch 16 bombers per side in a single wave.
So maybe those attack craft aren't so colossal?
It is also said Marauder bombers were used for the same role before Starhawks became standard issue. We sort of know how big a Marauder is -L 19, W 24, at least according to the first wiki I found, but that could also have been measured wrong, or produced out of scale.
Point is, how could a drastically smaller bomber do the job of the current ones? How can current Thunderhawks outfitted for a bombing run be relevant at all?
I could also have made a mistake in my measurements of course.
Or maybe the cruiser is supposed to be over 15 kilometers long. You'd think they'd plan these things through and release some official data so their players don't spend two decades speculating...
And to close off with something lolWTF, here's one from the other end of messed up estimates:
I don't remember the title, but it WAS an official Black Library relase; Some confused author wrote, a Battle Barge has 1Km (1000 meters, or 1.6 miles) thick ARMOR PLATING...
...Which would make the vessel large and heavy enough to crumple into a spherical shape due to it's natural gravity, but hey, you got paid either way...