Save Pages documents to memory stick; zipped folder issue

Start over. Make a new folder on your macOS Desktop. Copy your Pages documents into it. Right-click on that folder and select Compress "Folder name". Now you have a new zipped folder on your Desktop. Drag and drop that onto your mounted USB stick.

Although you can store Pages documents on Google Drive, keep them away from Google Docs, as it will see them as zip files with a "pages" extension name, and attempt to unzip the Pages document. When that happens, the Pages document is permanently damaged.

If you have zipped a folder containing Pages documents, you can drag and drop that on a external USB stick, ideally formatted as exFAT (incase your Zip file is over 4 GB). Pages cannot open a zipped folder, but double-clicking that zipped folder in the Finder will simply unzip it so you can again access the Pages documents within it.