The Solar Impulse plane has taken off for the final leg of its bid to cross the US on solar power alone.
The craft set off at 04:56 local time (08:56 GMT) on Saturday from Washington DC on a course for New York’s John F Kennedy airport.
Pilot Andre Borschberg anticipates a journey time of about 21 hours.
The Across America transcontinental bid began in San Francisco, California, and included stopovers in Phoenix, Arizona, Dallas, Texas, and St Louis, Missouri.
The Solar Impulse HB-SIA has the same wingspan as an Airbus A340 but at a weight of just 1.6 tonnes. By comparison, a fully laden A340 weighs about 370 tonnes.
The plane’s wing and stabiliser are covered with nearly 12,000 solar cells, which drive its four propellers and charge the plane’s 400kg of lithium-ion batteries for night-time flying.