Microsoft released their first expansion pack for Flight Simulator in years, called Flight Simulator X: Acceleration, to the US market on October 23, 2007 rated E – E10+ for mild violence and released to the Australian market on November 1, 2007 rated G. Acceleration introduces new features, including multiplayer air racing, new missions, and three all-new aircraft, the F/A-18A Hornet, EH-101 helicopter and the P-51D Mustang. In many product reviews, users complained of multiple bugs in the initial release of the pack. One of the bugs, which occurs only in the Standard Edition, is that the Maule Air Orion aircraft used in the mission has missing gauges and other problems, as it is a Deluxe Version-only aircraft.

The new scenery enhancements cover Berlin, Istanbul, Cape Canaveral and the Edwards Air Force Base, providing high accuracy both in the underlying photo texture (60 cm/pixel) and in the detail given to the 3D objects.

Flight Simulator X: Acceleration can take advantage of Windows Vista, Windows 7, and DirectX 10 as well.

The expansion pack includes code from both service packs; thus, installing them is unnecessary.