"What would happen if a MacBook and an iPad hooked up?"

That was the question Apple CEO put to the audience at the Back to the Mac event. The answer - the new, complete aluminium uni-body, instant-on, MacBook Air.

Jobs described the new design as "the future of notebooks". And there's two of them as well. Well, four, if you count all of the various spec models.

As rumoured, there are 13.3-inch and 11.6-inch models, both with very similar specs.

The new MacBook Airs are just 17mm thick at their fattest point, and 2.8mm at their thinnest. The 13.3-inch weighs just 1.3kg, with its little brother 300g lighter than that.

They both pack SSD storage, rather than HDDs and are powered by Core 2 Duo processors, 2GB of RAM and Nvidia GeForce 320m GPUs.

Despite their compact size they pack full-sized keyboards, full-sized glass trackpads, stereo speakers and FaceTime cameras.

You'll get 7 hours of Wi-Fi usage with the bigger model and 5 hours with the smaller one. Both have a standby time of an incredible 30 days.

Display wise, the 13.3-inch model has a 1440 x 900 resolution and the 11.6-inch one has 1366 x 768. Both have LED backlit screens.

The new MacBook Airs are available today (in the States at least) priced from £849.

For that you'll get the 11.6-inch model, with a 1.4GHz CPU and 64GB of SSD storage. For £150 more you can double your storage to 128GB.

If you want the 13.3-inch MBA, you're looking at £1099 for a 1.86GHz processor with 128GB of SSD space and £1349 for the top dog - the 256GB version.

The US prices, in case you're wondering are $999, $1199, $1299 and $1599.

- PHOTOS: MacBook Air (2010) hands-on