Tradewinds

Aethersphere

The skies directly above the Saltsea are called the Tradewinds. It is a perilous zone where ayrships must brave the threats of tidal waves and boiling steamjets during the day, and hungry tentacled leviathans at night. One must also watch for falling debris from ayrlands skimming along the Whitesea above, and for the suffocating clouds of violet aether that vents downwards from their reefcrusts. Then there are the Mor'Rahan kiterayders, riding on the backs of their shockfang mantas and armed with poison-tipped harpoons. They lurk behind rocky spires and sand-skayrries ready to strike unwary merchant ships.
Despite these dangers, traders still favor spending most of their time in the aethersphere. Any trader worth its salt needs to haul heavy. That means flying lower, and making frequent stops at the sand-skayrries - low-flying desert ayrlands where they can stop to drill and refuel on flux. Haulers also need all the lift they can eke out, so they sail beneath the Whitesea to keep clear lines of sight to any active seastacks where they can catch thermals.
Trade frigates would be smart to travel with an escort on birdback, or in smaller scouting ships, who can survey periodically to report on events above and clear the ship to rise and breach the Whitesea when it is safe.