We construct noncompact solutions to the affine normal flow of hypersurfaces, and show that all ancient solutions must be either
ellipsoids (shrinking solitons) or paraboloids (translating solitons). We also provide a new proof of the existence of a hyperbolic
affine sphere asymptotic to the boundary of a convex cone containing no lines, which is originally due to Cheng-Yau. The main
techniques are local second-derivative estimates for a parabolic Monge-Amp`ere equation modeled on those of Ben Andrews and
Guti´errez-Huang, a decay estimate for the cubic form under the affine normal flow due to Ben Andrews, and a hypersurface barrier
due to Calabi.