One of the greatest features of Airmail are labels. However for labels to be fully leveraged you need to be able to use them properly as search tokens using Boolean logic (AND,OR,NOT). At least with iCloud servers this does not work yet.
Joe Fletcher commented
I'd like a Smart Folder / search such as:
label:"The Company" or from:email@example.com
FYI, I meant for this comment to apply to Airmail for mac OS
Yes! In addition, does anyone know how to get Airmail to understand labels that include a space?
Agreed. A search for "label:xxx AND yyy" does not work properly. It appears that the search processes the "AND" as an "OR".