I'm well on my way to upgrading from my lowly Barracuda to a respectable blimp (cause I love being a tank in combat), and need advice on what the pros/cons are for each.

1. Cargo Upgrades
It says on the wiki page that the Leviathan cannot be upgraded or it will drop in CKPH due to how slow it is. Is this still true? Does this also apply to the Bismarck?

2. Combat
While the Leviathan looks incredibly imposing with it's 10 guns, they're all medium guns. Are the Bismarck's 6 large guns more powerful in a direct comparison of damage capability? Does the giant gap in the front of the Bismarck cancel out the advantage of all large guns?

3. Speed
Being able to buy nearly 700 crates at a time is awesome, except for the fact that high-tier commodities change like a girl changes clothes, so with the speed of a blimp, one can't really plan out a 20-leg flight and expect to make the same profit that the map displays when they start it, unless trading wood/fish/food/paper. Now, that's just the nature of blimp trading, but the Bismarck is almost twice as fast as the Leviathan. Does this make it better for trading, or are they both equally difficult to work with?

4. Speed Upgrades
The Bismarck has 2 engine slots, which, if the person using it has any sense, would be used to upgrade it's speed. Do those two slots make that big of a difference in terms of CKPH?

Trading: Both craft should be upgraded with a lightweight shell and a streamlined hull for CKPH, and the Bissy takes an r sticker and port and polish. If creative storage skill is maxed, these upgrades take the Levi from 93 thousand to 102 thousand. The Bissy rises from 62 thousand to 84 thousand. All cargo upgrades on either craft still do hurt the speed more than they help the cargo space. While the Bissy is faster (171 kph versus 110 kph) it still isn't flexible enough to overcome the Levi's CKPH. Levi has better range, and may fly a shorter route in some areas.

Combat: The Bissy is shorter, and has longer reach with its larger guns, which means it'll start pounding enemies sooner and be in their arcs for less time. Its speed is also far more tolerable in combat. It'll have a much easier time with towers. Armor class, silhouette, and combat upgrades are about the same for both craft. Levi has better DPS but it's hard to get a full broadside on most targets. The big gap on the front of the Bissy isn't really a problem, since it can spin around like a top, and it won't be chasing anything anyway.

Overall: The airships got pretty shafted by the upgrade system. Planes with better upgraded CKPH than the Levi include the Bullfrog, Cetacea, Havoc, Spectre, and all trade and performance planes above its tier. They're better at combat than they are at trading, and the Bissy is the best combat airship.