Microsoft cofounder Paul Allen on Tuesday announced plans for a new space travel system that would use the largest airplane ever built to launch rockets carrying cargo and eventually humans into space. \"It will keep America at the forefront of space exploration,\" Allen told reporters. In a collaboration with aerospace pioneer Burt Rutan, Allen\'s new company Stratolaunch systems aims to build a massive carrier aircraft that will tote a multi-stage booster rocket built by US company SpaceX. The aircraft aims to be able to deploy the rocket and send cargo into low-Earth orbit. The first flight could take place in five years. \"The air-launch-to-orbit system will mean lower costs, greater safety, and more flexibility and responsiveness than is possible today with ground-based systems,\" the company said in a statement. \"Stratolaunch\'s quick turnaround between launches will enable new orbital missions as well as break the logjam of missions queued up for launch facilities and a chance at space.\" The aircraft is planned to \"use six 747 engines, have a gross weight of more than 1.2 million pounds (544,000 kilograms) and a wingspan of more than 380 feet (117 meters),\" press materials said. \"Systems onboard the launch aircraft will conduct the countdown and firing of the booster and will monitor the health of the orbital payload.\" Allen and Rutan\'s project, SpaceShipOne, was the first commercial craft to complete a suborbital flight in 2004, and was followed by Virgin Galactic\'s commercial suborbital SpaceShipTwo Program.