  A precise prediction of the neutrino flux is a critical input for achieving
the physics goals of accelerator-based neutrino experiments. In modern
experiments, neutrino beams are created from the decays of secondary hadrons
produced in hadron-nucleus interactions. Hadron production is the leading
systematic uncertainty source on the neutrino flux prediction; therefore, its
precise measurement is essential. In this proceedings, recent results and
ongoing analyses of hadron production measurements by the NA61/SHINE
experiment, as well as prospect for achievable precision on the flux
predictions of T2K and Fermilab-based long-baseline neutrino experiments, will
be presented. In addition, the necessity and prospects of further hadron
production measurements by NA61/SHINE at CERN and the EMPHATIC experiment at
Fermilab for the next generation neutrino experiments will be discussed.
