Apple could be planning to introduce a 15-inch notebook next March, according to a report from DigiTimes which speculates that the device could be a new Macbook Air model or a thinner MacBook Pro.

The report cites ‘upstream sources’ that have recently begun shipping components for a range of new devices, one of which is believed to be 15-inch although as yet the identity of the device is unknown:

Estimated by the product planning, mass shipments of the notebook device will start in March and could be cataloged in either the MacBook Air or MacBook Pro line. Apple currently has three screen sizes for the MacBook Pro – 13.3-inch, 15.6-inch and 17-inch.

The new model is rumoured to have the shape of a MacBook Air although it is suggested that thinness of the machine could mean that — in order for it to be equipped with an optical drive as standard —  the model would not be released until “a later time”. That’s assuming that Apple doesn’t change things up and ship a different kind of Pro altogether of course.

Apple has been strongly linked with the possible introduction of 15-inch notebooks, according to a recent report from Japan.

Statistics from Morgan Stanley reported today showed the significance Apple is placing on the MacBook Air which grew from accounting for 5 percent of the company’s US notebook shipments in January, to 28 percent of shipments in October.