Solar Impulse II, a plane exclusively powered by solar energy, began the trans-Atlantic stage of its planned world tour on Monday, taking off from New York's John F. Kennedy International Airport for Seville in Spain.
The plane, which is attempting to become the first aircraft of its kind to circumnavigate the world, took off at 06.60 GMT and is expected to land about 90 hours later, with arrival scheduled for Thursday, Efe reported.
During this stage, one of the most difficult because it will last four days and four nights, Solar Impulse II is being flown by one of its inventors, Bertrand Piccard.
The plane will fly non-stop if the weather allows it.
Last year, the other engineer involved in the project, Andre Borschberg, flew five days and nights across the Pacific Ocean, breaking a record and demonstrating that the airplane is able to fly non-stop.
This year, with a round-the-world flight on an aircraft powered only by solar energy, the developers hope to raise awareness among governments and persuade them to support technology solutions to protect the environment.
So far, Piccard and Borschberg, taking turns as pilots, have completed 80 per cent of their circumnavigation quest.
In the previous stage, Borschberg flew 129 km (80.1 miles) from the Lehigh Valley in Pennsylvania to New York.
After landing in Europe, Solar Impulse II will be ready for the flight to Abu Dhabi, in the UAE, where the journey began in March 2015.