One of the richest men in the world is going to build the biggest airplane ever. And then he is going to use it to launch rockets.Paul G. Allen, the billionaire co-founder of Microsoft, said Tuesday that he was entering the rocket business with a concept seldom used until now: a plane that can take off the conventional way and then, at 30,000 feet, launch a rocket to orbit, carrying with it satellites, supplies and — eventually — people. The first rocket launching could be as soon as 2016. “You have a certain number of dreams in your life that you want to fulfill,mulberry bags” said Mr. Allen, an avid philanthropist who has also financed efforts like a radio telescope listening for alien transmissions, “and this is a dream that I’m very excited about.” The airplane that his new company, Stratolaunch Systems, plans to build will be larger and heavier than the Spruce Goose, Howard Hughes’s record-setting flying boat that flew, just once, in 1947. With wings that will stretch 385 feet — longer than a football field — it will dwarf the double-decker Airbus A380, which is the biggest commercial passenger plane flown today. It will take off from a runway, fly to a normal cruising altitude and then drop off a rocket, eliminating the need for costly launching pads. “With government-funded spaceflight diminishing, there is a much expanded opportunity for privately funded efforts,” Mr. Allen said. He noted that NASA had ended its space shuttle program this year, scrapped plans to return to the Moon and begun relying solely on Russia for launching astronauts to the International Space Station. mulberry saleHe said his new effort would help keep “keep America at the forefront of space exploration.” Mr. Allen thus joins the ranks of tycoons who are placing big bets on the heavens. The most prominent is Richard Branson, whose Virgin Galactic subsidiary is planning to fly tourists on short jaunts to the edge of space. Other big names are Elon Musk, who used his fortune as a founder of Paypal to establish SpaceX, a rocket maker that is racking up contracts with NASA, and Jeffrey P. Bezos, the Amazon.com founder, who has a space company called Blue Origin. His new project draws in a mixture of space industry people, old and new. Mr. Musk’s company — the Space Exploration Technologies Corporation, or SpaceX — will build the rockets that Stratolaunch plans to launch. Michael D. Griffin, a former NASA administrator who has been supportive but skeptical of the emerging commercial space industry, will be on Stratolaunch’s board of directors. Stratolaunch will have headquarters in Huntsville, Ala., which is known as “the Rocket City” because of its role in the history of spaceflight, mulberry bags for saleand an aircraft hangar in Mojave, Calif.Mr. Allen is the sole investor, putting only his own money at risk. He declined to say how much he planned to spend. “Obviously, this is not inexpensive,” he said. His new company aims to use the same strategy that won the X Prize, and supersize it. For the X Prize, he and Mr. Rutan took a rocket called SpaceShipOne, slung beneath a carrier airplane, and lofted it high into the sky before launching it, with a pilot on board.