The CFFA3000 supports an internal USB drive. Unfortunately, you need you remove the cover of Apple to gain access. Many of us use a USB extension cable to bring this port to the outside world for easy access.
Every so often a neat item appears on eBay. This is a 3-ft USB extension cable from D-Link and it is designed for use with a USB drive. This item, 170942966023, is selling for $3.59 and includes shipping. I decided to get one for my CFFA3000.
I purchased several cables similar to this one some time back. They are very handy.