A generalization and short proof of a theorem of Hano on affine vector   fields
  We prove that a bounded affine vector field on a complete Finsler manifold is a Killing vector field. This generalizes the analogous result of Hano for Riemannian manifolds. Even though our result is more general, the proof is significantly simpler. 
D\'avid Csaba Kert\'esz and Rezs\H{o} L\'aszl\'o Lovas
math.DG