Two Swiss aviation engineers have revealed the prototype of a solar-powered plane designed to make the first solar powered flight around the world in 2015.

Titled the Solar Impulse 2, the plane was designed to have "unlimited endurance," allowing the pilot to fly across continents for hours on end without any fuel, CNN reported Tuesday. 

"What we have now is the first airplane in the world which has unlimited endurance," Andre Borschberg, who co-created the plane, told CNN. "It can fly a day and a night, it can fly a week, it can fly a month- theoretically it can fly a year.

"It's the most energy efficient airplane ever built," Borschberg told CNN.

Borschberg, along with co-creator Bertrand Piccard, plan to fly the plane non-stop for five days and nights around the world.

The sun-plane, which took 12 years to design, is made from carbon fiber and weighs about the same as a family car, CNN reported. The wings are covered with 17,000 solar cells that power four electric motors. The plane's lithium batteries are able to store enough solar energy throughout the day to allow the plane to fly at night.

The plane is also designed to keep the pilot as comfortable as possible- with storage space for food and water, and a seat that turns into a toilet.

Piccard and Borschberg told CNN they spent a lot of time physically and mentally preparing themselves for the week-long flight.

"You have to be ready in your head to really visualize all the solutions," Piccard said. "All the positive emotions around the flight that will last five to six days alone over the ocean, and also visualize how to enjoy it- otherwise it's very, very difficult."

But that may not be a problem for Borschberg, who already set a record when he flew the Solar Impulse 2's predecessor in the first solar-powered overnight flight in 2010, which lasted 26 hours, CNN reported.