I checked drugstore dot com's shipping policies -- they may be instructive on what is allowed to be shipped by air and what is not -- it appears that DOT requirements on what can be delivered by air are what control:
DOT restrictions on air shipping
Most of our packages are delivered by a combination of air and ground transport. But the U.S. Department of Transportation (DOT) prohibits air shipment of items that could contribute to an onboard fire or other mishap.
Restricted items include:
Aerosol-type products or medications in pressurized spray cans, such as: hairspray, shaving cream, and inhalers.
Products that contain flammable volatile, or corrosive chemicals, such as: fragrances, nail polish, bunion treatments, and nail polish remover.
We're committed to getting your order to you as quickly as possible, but we also want to do it safely and responsibly, in compliance with DOT rules. That's why we require ground-only delivery, at our Standard Shipping rate, for orders that contain DOT-restricted products.
There is no spoon.