Scandinavian source circa the 1200s from Old Norse 'a lopt', where lopt meant 'up in the air'. 

Aloft not only refers to going up in a balloon or plane, but sailors also went aloft in the rigging on wooden sailing ships, usually to unfurl the sails or to scan the horizon for hazards or other ships. 

The term 'a loft' can also refer to an attic or a room directly below the roof of a house or other building.