Cargo delivery is a job that you an work on waterdeep.
Once you visit a job site you can be hired as a cargo delivery driver for airships.
To start take your airship to a cargo courier and request a cargo job.
The first 50 jobs only require you to deliver a single cargo crate.
After that you have to deliver 2 crates.
Once the crate is at the destination unload it and comeplete the job.
usually you will repark your ship after you complete your cargo as well