You need to make sure that external/travel drive is formated to FAT32 then you should be able to copy files to and from this drive.
Plug in travel drive to your mac and open Disk Utility (via spotlight or /Applications/Utilities)
Select travel drive on the disk utility side bar. then from main part select Erase and as a format choose MS-DOS (fat) and then erase.
FYI: above steps will erase all data which currently stored on this drive so you might take a copy of it.
One additional note - the cloud
based on my experience schools have used google and other cloud based technologies to support their students. Migrating away from the usb as a storage medium all together.
please touch base with the school to see if your child has been assigned a google or some other cloud based userid and password that can be used to access the documents in question.
Thanks for the formatting tip, but in my illiterate ways I/we need just a bit more help. Unlike the PC the Mac doesn't seem to have something like the Windows Explorer where you can drag a file from the documents sections down to flash drive or does it. We are a family of PC users since 1990 and just recently purchased our first IMac so our learning curve is extreme. Any walk through help would be appreciated.
The Mac's Finder is the same thing as the Windows Explorer. Insert your Flash drive and you will see it become available in the sidebar of a Finder window under "Devices." If it does not appear here then try going to the Finder menu, select Preferences, and then in the Sidebar section checkthe option to include "External disks" in the sidebar (you can also check the option in the General section to have disks show on the Desktop).
When this is done, you can then drag any file from any accessible location in the Finder to the disk device in the sidebar and have it copy to the disk. You can also select items (use the Command and Shift keys in selecting to select more than one item) and then press Command-C to "Copy" followed by going to the disk, opening it, and pressing Command-V to paste the items to the disk and effectively copy them that way.
When finished select the disk and press Command-E to eject it, which can also be done by right-clicking it and choosing Eject, dragging it to the Trash from the Desktop, or by clicking the little Eject button that appears when you hover your mouse over the drive in the sidebar.
1) Unless something has changed?
Doesn't a icon appear on the desktop? Has it been moved?
Double click on the flash USB drive.
Drag & drop files to flash drive folder.
2) You can save from word & powerpoint etc directly to the flash drive.
3) I'd look into dropbox. If you can get to the internet from the school computer you can at least read from the dropbox folder.