VMS Eve

VMS "Eve" (Tail number: N348MS) is a carrier mothership for Virgin Galactic and launch platform for SpaceShipTwo-based Virgin SpaceShips. 
VMS "Eve" was built by Scaled Composites for Virgin Galactic. The "VMS" prefix stands for "Virgin MotherShip".
Public launch.
The aircraft was named after Evette Branson, the mother of Richard Branson, Chairman of the Virgin Group. The jet plane has nose art of a blonde woman holding a banner with the Virgin Galactic logo. The image is based on how Evette Branson looked when she was younger and is called "Galactic Girl". The aircraft was officially launched on July 28, 2008, in Mojave, California, the United States, at the Mojave Spaceport, home of Scaled Composites. On December 12, 2008, the aircraft performed first taxi tests, and a week later the maiden flight. "Eve" is being used in the Virgin Galactic testflight program, preceding entry into commercial usage.
Burt Rutan has dismissed fears that pressurization cycles might induce fatigue failure in the composite structure. Richard Branson has also announced that it will be highly fuel efficient.
Flight test program.
The initial flight occurred on 12 December 2008, after an initial low speed taxi test was carried out at Mojave followed by a high speed taxi on 16 December. By September 2009 the flight envelope was extended to 50000 feet. the total flight time for WhiteKnightTwo is 333.96 hours.