CARL Frederickson’s airborne home is not just a flight of fancy.

In last year’s cinematic 3D hit Up, the 78-year-old retiree escapes life in a seniors’ home by attaching hundreds of balloons to his house and flying to South America.

It seemed like a great idea at the time, but can it be done?

According to a team from National Geographic, yes.

Sort of.

Ben Howie, executive producer of the new Nat Geo TV series How Hard Can It Be?, said the team “found it is actually close to impossible to fly a real house”.

So instead they built a lightweight one, attached it to 300 balloons and watched it lift off and soar some 3500m above California’s High Desert.

In doing so, they set a world record for the largest cluster balloon flight ever attempted, as well as providing extra inspiration for cranky old widowers who never realised their dreams and boy scouts the world over.

“What we can do is kind of fly a lightweight house and fly it safely with people inside,” producer Ian White said.

Excuse me? Did he say, “people inside”?

Yes, Nat Geo’s Up house, measuring 4.8m x 4.8m x 5.5m, was inhabited while it sailed across the Californian desert.

From the Herald Sun