So I am going to setup a brand new 2017 MacBook Air for a friend early next week when it arrives. Once I got it set up and running as it should be... Can I use a USB 3.0 flash drive to make a time machine back up. Kinda like a recovery media on a windows laptop. He not know much about computers but if/when he messes it up it could help me get him running again sooner. Is it possible to use a flash drive? He ordered the 128GB model and with what little data there at beginning I'd guess a 16GB or 64GB would be big enough for the one time use. Advice or input on this sort of thing from anyone?