Massive stars regulate galaxy evolution and star formation. They pour excess radiation into their surroundings in birth and life, and populate galaxies with metals in death. However, observational constraints on massive star formation are challenging due to the high extinction and inherently complex structure of environments which form massive stars. Outflows provide a unique window to probe the deeply embedded massive protostars, constraining models of massive star formation. In this study, we investigate 17 massive protostars selected from the SOFIA Massive (SOMA) Star Formation Survey, searching for active atomic, molecular, or ionized outflows. Each source was observed with the Far-Infrared, Field-Imaging Line Spectrometer (FIFI-LS) in the prominent [OI] lines at 63 μm and 145 μm, as well as the [OIII] line at 52 μm and the CO(14-13) line at 186 μm, characterizing the interactions between the core and surrounding environment. We confirm detection of [OI] in all sources, CO in most, and probe the emission of [OIII] from a small subset of sources, which would be a novel tracer of massive energetic shocks in protostellar systems. In particular, we study the source G011.94-00.62, where we find a previously undetected, highly ionized bipolar outflow. We categorize outflow morphology for our 17 sources, and compare our results with those established in literature infrared/radio imaging. We measure the line flux from each spectral species in each source, investigating the [OI] 63/145 and CO/[OI] flux ratios and relationship between line flux and bolometric luminosity. Modeling with RADEX is employed to compare observed line ratios with those predicted by non-LTE radiative transfer simulations. We also measure continuum photometry for all of the sources, generating spectral energy distributions to inform on protostellar characteristics.
