Latest: Since this article was published, the mystery starfighter has been confirmed as an updated version of the X-wing starfighter. Higher resolution images show the detail of the seam where the wings, or S-foils, split to create the distinctive X-wing shape.
Original outdated article continues below.
The starship resembles an X-wing similar to those seen in the classic Star Wars trilogy, but seems to lack the split wing arrangement, leading to fan speculation that it may be based on the expanded universe's Z-95 Headhunter.
The dual engine set-up is similar to the Z-95 version seen in The Clone Wars TV series, so this starfighter may represent an upgraded model of those ships used by clone trooper pilots.