This two-ship combo is Burt Rutan's contribution to privately-funded space travel. The twin jet-powered mother ship is called "White Knight", and the daughter ship (the smaller ship under the bigger White Knight) is the rocket-powered "SpaceShipOne". This is likely to be the first private plane to make it into outer space.
On its first flight on December 17, 2003 (the 100th anniversary of the Wright Brothers' flight), Burt Rutan's Scaled Composites launched its rocket-powered offspring ("SpaceShipOne") from the White Knight carrier aircraft over the Mojave Desert. SpaceShipOne ignited its rocket motor and blasted to 67,800 feet on its first flight.
SpaceShipOne's next flight was on April 8, climbing to 105,000 ft at Mach 1.6.
Update: On June 21,2004, SpaceShipOne really took off, climbing to about 215,000 feet / 40.7196974 miles / 65.5321317 km. This is genuine space travel!