The 11" MBA is 1366 x 768, but the 13" MBA is 1440 x 900. The 15" MBP has been 1440 x 900 since 2006 but in 2010 added an upgrade option to 1680 x 1050.

As far as I know, the 11" MBA is the only Mac to ever offer that resolution.

As it turns out, I get that res on my 11"

13" MacBooks are 1280×800.