Zip and extract

S3 storage can’t make or open archives itself. AirSCP does it on your Mac, as a job in the Transfers list: it downloads, zips or unpacks, and uploads.

Steps

Download as a .zip

Select the items and choose File ▸ Download as .zip….
Click Download. The .zip lands in the folder the left pane shows (or in your Downloads folder).

Compress in the bucket

Select the items and choose File ▸ Compress….
Click Compress. A .zip appears next to the items (Archive.zip for several items).

Extract

Select a .zip, .tar, .tar.gz, .tgz or .gz file.
File ▸ Extract Here puts its items in the same folder. When an item of the same name is there already, AirSCP puts them in a new folder named after the archive instead: nothing is replaced.
File ▸ Extract to New Folder always puts them in a new folder.

Tips

Zips are made with macOS’s ditto, without Mac-only extras, so they open on Windows and Linux too.
The job needs room on your Mac for the items while it works. It cleans up when it ends.
Like any transfer, the job can be paused (it starts again on Resume), cancelled or retried.