After a long, long wait, Google Docs/Drive added offline support only a few months ago. But it only worked for documents. Now, Google is adding support for presentations as well. Slides now works in offline mode, meaning you can create, edit and present without an internet connection.
You do need to enable the feature first and it only works in Chrome and Chrome OS, if you haven't already done that for docs.
Your more recent documents, of any kind, will be synced and made available offline for viewing, and some documents and now presentations, for editing.
"Any new presentations or changes you make will be automatically updated when you get back online. So you can continue polishing slides on your next flight, and head to your upcoming presentation without worrying about whether there's going to be wifi," Google explained
There's no word on when spreadsheets are supported, through Google said it was working on it when it first unveiled offline support in June.