Falling, plummeting, hurtling like a meteor toward Earth. Jennifer waited for her heart-pounding date with gravity to near its inevitable end, then spread her arms like a bird. Unseen wings unfurled, and catching an updraft on the way down, Jennifer rocketed back up, higher and higher, until she was soaring, gliding, sailing across the clouds once more.

So, she thought, this was what it felt like to fly. She used to wonder about that when she was little. Now that s...