Using a USB or External Hard drives with CDJ or 1000SRT

Can I just use a USB or External Hard drive with CDJ-2000 or DDJ 1000SRT? If I don't want to bring my laptop can that work? If yes do I have to use record box or can I just play songs off of my external hard drive or USB? I will not have access to wifi when I do this

Also I just bought a DDJ-FLX10 and doesn't seem like I can plug a USB stick in anywhere, can I?  

Please let me know thanks