The absence of an in-built 3G modem and iPad-style micro-SIM slot is the most surprising omission in the specification of the new Airs. It's about time Apple acknowledged that most customers want to use the cellular networks and started to fit modems to the full range of MacBooks. While they could possibly argue that weight and space considerations are responsible for the omission of 3G on the new Airs, no such restrictions apply to the larger models in the range. So, unfortunately, after the ease of connection with the iPad, we are now back to plugging in a USB modem or fiddling with a MiFi unit. I would place built-in 3G connectivity as top of my wishlist for the next upgrade.