MacBook Air Review
There is no FireWire on the MacBook Air, so Apple had to redo Migration Assistant to get around that limitation. “Great, Apple finally fixed Migration Assistant to work over USB 2.0!”
Bzzt! Thank you for playing. That would be too easy, my Apple-faithful friends. Instead, Air users who want to use Migration Assistant must do so either over WiFi (the default setting) or a USB Ethernet adapter.
…Don’t waste even a single minute of your time on WiFi. If you really must transfer your settings, buy a $29 Ethernet adapter.