AeroPython/scikit-aero ? reverse-engineered prompt

Build me a Python package for aeronautical engineering calculations that feels clean and easy to use.

I want it to handle common air and gas dynamics calculations, with SI units by default and support for NumPy arrays so people can pass in single values or whole arrays. Please include standard atmosphere properties up to 86 km, and make the interface feel natural for Python users, not clunky or overly academic.

Set it up as a proper installable library with documentation and tests, and make sure the examples in the docs are enough for someone to start using it quickly. If you need to check current Python packaging or documentation best practices, look up the latest docs online. Keep it simple, well organized, and reliable, with a focus on practical aerospace calculations people can actually use.