Check out Aviation Week's On Space blog for more on newly formed Swiss Space Systems' (S3) plans to orbit small satellites using an Airbus A300 carrying an unmanned shuttle. There is video there of how the launch concept will work when suborbital test flights begin in 2017.
S3 founder Pascal Jaussi says the A300 has been chosen because it is certified to operate from commercial airports and fly in civil airspace to deliver the shuttle to its 33,000ft release altitude, the return to base and a rapid turn-around for the next launch. Also, Jaussi notes, the A300 already has been certified to fly a parabolic zero-g trajectory, a capability ESA uses for microgravity research and astronaut training.
S3 intends to operate the shuttle-carrying A300 from a new spaceport to be built at Switzerland's Payerne airport. Others are planned to follow in other parts of the world. Video of its spaceport design concept is also on the blog.