Microsoft co-founder Paul Allen and aerospace pioneer Burt Rutan are building the world’s biggest plane to help launch cargo and astronauts into space, in the latest of several ventures fueled by technology tycoons clamoring to write America’s next chapter in spaceflight. Their plans, unveiled Tuesday, call for a twin-fuselage aircraft with wings longer than a football field to carry a rocket high into the atmosphere and drop it, avoiding the need for a launch pad and the expense of additional rocket fuel. Allen, who teamed up with Rutan in 2004 to send the first privately financed, manned spacecraft into space,...
