A solar-powered airplane is set to embark on a historic flight across the United States this morning. Weather permitting, Solar Impulse will leave the Bay Area at 6 a.m. PST, and arrive in New York about two months later, after stopovers in Phoenix, Dallas, St. Louis, and Washington, D.C. With 12,000 solar cells built into the wings, the plane is designed to fly on sunlight alone. Check out the livefeed above, and read more about Solar Impulse here.