Mountain wave (MW) propagation and dynamics extending into the upper mesosphere accompanying weak forcing are examined using in situ and remote-sensing measurements aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V (GV) research aircraft and the German Aerospace Center Falcon. The measurements were obtained during Falcon flights FF9 and FF10 and GV Research Flight RF22 of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) performed over Mount Cook, New Zealand, on 12 and 13 July 2014. In situ measurements revealed both trapped lee waves having zonal wavelengths of λx ~ 12 km and less, and larger-scale, vertically propagating MWs primarily at λx ~ 20–60 km and ~100–300 km extending from west to ~400 km east of Mount Cook. GV Rayleigh lidar measurements from 25- to 60-km altitudes showed that the weak forcing and zonal winds that increased from ~12 m/s at 12 km to ~40 and 130 m/s at 30 and 55 km, respectively, enabled largely linear MW propagation and strong amplitude growth with altitude into the mesosphere.