I’ve always been fascinated with air travel.

As a kid growing up in Wisconsin, I would attend the annual summer fly-in of the Experimental Aircraft Association in Oshkosh. It’s truly a spectacle -- on display you can find everything from World War II bombers to ultralights to the SR71; one year they even had the Harrier jet demonstrate a vertical take off.

One thing they never had was a solar-powered aircraft. That’s because, until recently, such a thing did not exist.

The Solar Impulse, the world’s first solar-powered airplane, is charting a new course for air travel. A cleaner course. A practical course -- why shouldn’t we use all of the renewable solar energy hitting the wings of airplanes each day?

As Solar Impulse continues its landmark tour, the plane is on track to become the first solar powered aircraft to make it entirely around the world using only the sun’s energy.

By doing so, they are breaking the “solar barrier” -- perhaps no less important than when Chuck Yeager broke the the sound barrier in 1947.

People used to say solar was too expensive; that it couldn’t provide enough power for our homes, schools and businesses. They were wrong.

We just hit one million solar installations in the United States -- a major milestone achieved through good policy and public commitments to using renewable resources. Solar energy now not only powers our homes, schools and businesses; it’s starting to power our cars, trains, and now, even airplanes.

I’ve been itching to see Solar Impulse for myself, so when it landed near my home in Arizona last week, I seized on the opportunity.

The first thing you notice about the airplane is its massive wingspan. In fact, 2,200 square feet of solar panels sit atop the wings, powering four large propellers and other electrical equipment.

In the center of the aircraft, you notice that the cockpit seems relatively small. To cut back on wasted space and weight, the plane only houses one pilot at a time.

Having only one pilot makes the journey especially challenging. Before landing in the United States, the crew set a world record for the first solar powered solo flight over the Pacific Ocean. It took five days and five nights to fly from Japan to California. The pilot, Andre Borschberg, told National Geographic he persevered using yoga, meditation and self-hypnosis, sleeping only in 20 minute increments.

We should salute these solar pioneers for pushing us to see all the ways renewable energy technology can advance our society. Truth be told, we’ll need solar powered air travel to reach a 100 percent renewable energy future. We need people like the Solar Impulse pilots and crew to continue to inspire the world to seek that vision with us. The “solar barrier” can and should be broken.