The ratio of the log of capacity to speed is roughly constant across the various forms of freight transit. Ships are slow but have massive capacity, trains are

The ratio of the log of capacity to speed is roughly constant across the various forms of freight transit. Ships are slow but have massive capacity, trains are faster with lower capacity, planes have extremely low capacity but damn they're fast. Zeppelins/dirigibles are extremely slow and extremely low capacity. They have some niche utility when endurance is required (you want to stay in the air for as long as possible) but shipping is definitely not one of those circumstances.