Looking out at the clouds from the side of the roaring prop plane, U.S. Air Force Tech. Sgt. Kate Parker battled a whirlwind of fear and exhilaration. Despite the deafening engine and shouted instructions, a surprising surge of calmness coursed through her, a stark contrast to her lifelong fear of heights. The military veteran skydiving instructors had framed the tandem jump as more than a physical feat—it was a leap of faith, a chance to...