There are few environmental sins worse than air travel. A few years ago, Friends of the Earth declared aviation “the world’s fastest growing source of greenhouse gases.” A report released in 2008 found that airlines might pour 1.5 billion tons of carbon dioxide into the atmosphere by 2025.

With numbers like those, it’s no surprise that the European Commission is wanting to shift some of the costs of such pollution back onto the airlines themselves. And with numbers like those, it’s very welcome to read of a plan from the European Aeronautic Defence and Space Company (EADS, for short) to develop an all-electric aircraft that it hopes could fly the skies within 20 years.

Here’s how the idea—which EADS calls an “upstream research concept, not a near-term commercial approach”—would work. The VoltAir, as the plane is tentatively dubbed, would be powered by enormous lithium-ion batteries, with energy densities of 1,000 Wh/kg. (Extrapolating from recent progress in battery research and development, EADS thinks this goal attainable in two decades.) The jumbo batteries would then power motors, which would drive counter-rotating propellers at the plane’s tail end. And as if it were some child’s toy, once the plane has landed, airlines could simply swap out the spent batteries with pre-charged ones, cutting down time currently spent refueling. An animation of the concept, which was presented at the recent Paris Air Show, can be viewed here.

Setting matters of conscience aside, EADS thinks an all-electric aircraft would also lend itself to a generally improved in-flight experience. The plane would be quieter, for one thing, both because the engines would be inherently less noisy and because they’d be sequestered at the rear of the plane. The novel shape of the fuselage EADS envisions would also make for a more spacious cabin, meaning less clambering over fellow passengers or squeezing awkwardly past them in the aisle.

EADS isn’t the first to envision all-electric aircraft. Model-sized aircraft have been flown for decades, in fact. In 2007, a few scientists made a splash by suggesting all-electric aircraft powered by superconducting motors could be on the horizon. And “electric,” of course, is not a panacea. While undoubtedly greener than what we have today—the VoltAir plane wouldn’t emit any carbon dioxide or nitrogen oxides in flight—not even an electric aircraft is guaranteed to be truly green. That massive battery has to be charged somehow, after all, and if it’s a coal-fired power plant that’s doing the charging, there would still be considerable greenhouse gas emissions involved.

Lastly, the design raises all sorts of questions over fail-safes and backups. Would there be auxiliary or emergency power of some sort? As a commenter on Inhabitat recently noted, here is an instance where a dead battery would be something quite more than a mere annoyance.