While much progress has been made in understanding tropical cyclone (TC) intensity change, skillful forecasts are still a difficult challenge. In a recent example, operational numerical models failed to forecast the rapid intensification of Hurricane Patricia (2015) from a tropical storm to an estimated 185 kt intensity in 36 hours as it became the strongest TC on record in the Western Hemisphere. Patricia then rapidly weakened at an unprecedented rate prior to making landfall on the Mexican coast, which was also not well captured by forecast models. In an effort to better understand the mesoscale processes involved in TC intensity change, analysis of research aircraft observations from recent field campaigns has been conducted. Results will be presented from research flights into Hurricane Patricia (2015) as part of the Office of Naval Research sponsored Tropical Cyclone Intensity (TCI) field experiment, and flights into Hurricane Rita (2005) from the National Science Foundation sponsored Hurricane Rainband and Intensity Change Experiment (RAINEX). In Patricia, a high-altitude aircraft equipped with a new high-density sounding system enabled full-tropospheric profiling of temperature, humidity, and winds throughout Patricia's inner and outer core. In Rita, multiple airborne Doppler observations allow for a new indirect retrieval approach to estimate the three-dimensional temperature and pressure perturbations in the eyewall region. The results of these analyses are consistent with recent studies indicating the importance of the radial and azimuthal location of convection in the TC eyewall, and help provide new insights into the dynamics and thermodynamics of TC intensity change.