Microsoft's new Surface Pro 4 ad targets feature gaps in Apple's MacBook Air

The ad highlights the fact that the Surface is equipped with a touchscreen and a bundled Surface Pen, and can be used with or without a keyboard. It also suggests that the Air is "slower, heavier, and a bit square," and notes that Surface users can log in faster thanks to Windows Hello biometrics.

Microsoft has regularly gone on the offensive with ads for the Surface line, looking to persuade people that its devices are a better value than Apple's. Most recently, the company used Apple's own marketing against it, arguing that the iPad Pro isn't a full-fledged computer, for instance because it can't run complete desktop apps.

Apple has largely sidelined the MacBook Air this year, its only real upgrade being a default 8 gigabytes of RAM on 13-inch models. Instead the company has focused on the 12-inch Retina MacBook, which is also considerably more expensive, starting at $1,299 versus the 13-inch Air's $999. The Surface Pro 4 starts at $899 — an official Type Cover is $130 extra, but the tablet can be paired with conventional keyboards and mice as well.