Jacob Christian Hansen Ellehammer (June 14, 1871 – May 20, 1946) was a Danish watchmaker and inventor born in Bakkebølle, Denmark. He is remembered chiefly for his contributions to powered flight.Following the end of his apprenticeship as a watchmaker he moved to Copenhagen where he worked as an electronics mechanic before establishing his own company in 1898. In the beginning he produced cigarette machines, beverage machines and other electronic machinery.