If you want to transfer big files between machines but have no wired connection, you may still be able to do it rapidly by wiring two laptops together directly. Most modern ethernet interfaces (e.g. those allowing 1000Base-T or “Gigabit Ethernet”) and all Macs since 2000 will auto-sense crossover mode. In plain English, the computers can talk to each other, without a relay (Router) in between. Another name for this is Auto MDI-X. You can find out a lot more than you ever wanted to know about Ethernet standards here. You can use a standard ethernet cable, which I always carry in my bag in case I find a hotel without Wifi – not as rare as you might expect. In the past, a crossover cable (not so generally available) would have been needed. Newer Macbooks need the Thunderbolt to Ethernet adaptor. I passed a 6Gb file from my Retina Macbook (10.10) to an HP Elitebook (Windows 7) in about 15s.
It’s a beautiful feeling when you realise all the hard work that has gone into making something that is intuitive (connecting two computers with a cable) both automatic and instant.
UPDATE: Trying the same again later -without changing any settings- Windows 7 on the Elitebook automatically designated the ad hoc network as a “Public” network, which turned off network discovery and file sharing by default. So helpful. If you’re not used to Windows, be careful. These crazy automatic settings can be confusing.