In this paper we evaluate new retrievals of the deuterium content of water vapor from the Aqua Atmospheric InfraRed Sounder (AIRS) with aircraft measurements of HDO and H<sub>2</sub>O from the ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) field mission. Single footprint AIRS radiances are processed with an optimal estimation algorithm that provides a vertical profile of the HDO/H<sub>2</sub>O ratio, characterized uncertainties, and instrument operators (or averaging kernel matrix). These retrievals are compared to vertical profiles of the HDO/H<sub>2</sub>O from the Oregon State University Water Isotope Spectrometer for Precipitation and Entrainment Research (WISPER) on the ORACLES NASA P-3B Orion aircraft. Measurements were taken over the Southeast Atlantic Ocean from 31 August to 25 September 2016. HDO/H<sub>2</sub>O is commonly reported in delta-D notation, which is the fractional deviation of the HDO/H<sub>2</sub>O ratio from the standard reference ratio. For collocated measurements, the satellite operator (averaging kernels and a priori constraint) is applied to the aircraft profile measurements. We find that AIRS delta-D bias relative to the aircraft is well within the estimated measurement uncertainty. In the lower troposphere, 1000 to 800 hPa, AIRS delta-D bias is −6.6‰ and the Root Mean Square (RMS) deviation is 20.9‰, consistent with the calculated uncertainty of 19.1‰. In the mid-troposphere, 800 to 500 hPa, AIRS delta-D bias is 6.8‰ and RMS 44.9‰, comparable to the calculated uncertainty of 25.8‰.