My mobile phone allows me to sync my contacts and calendar with Outlook on my main machine. I'm using a laptop as well and the sync application allows me to sync my contacts and calendar information back to Outlook on my desktop. I'm using POP3 and therefore I cannot sync all my mail folders with the server.
Is there a way I can have this "plug it in and it syncs" functionality with my email as well such as via a USB flash drive?
Sadly Outlook itself doesn’t contain a solution to directly sync between to machines. There are quite a few 3rd party pst-syncing applications for Outlook such as SimpleSYN and CodeTwo Outlook Sync but they usually only work via a network, simulating a client/server environment or sending additional specially crafted emails.
Sync add-in for USB
Easy2Sync for Outlook and Sync2PST also have an option to sync when both machines are not in direct contact with each other or when you prefer to use a USB flash drive or USB hard disk. When setting up the sync with Easy2Sync for Outlook you should look for the "bridge" function or the option "Far away".
Use mobile phone storage
My recommendation; sync it to the storage card of your mobile device. This way you keep all your data in one place and don't have to carry around an additional thumb drive. Just connect your mobile and both your mobile sync application and Easy2Sync or Sync2PST will sync your data.