Aircraft measurements of methane and carbon dioxide mixing ratios were carried out by Champion X at several facilities in New York State in 2021. This dataset includes the observed raw methane and carbon dioxide mixing ratios of the sampled facilites. Measurements were made using a single-engine Mooney aircraft where ambient air was drawn in through the rearward-facing inlets mounted on the wing of the aircraft. In situ methane, carbon dioxide, and water vapor were recorded using a Picarro G2401 cavity ring down spectrometer at 1 Hz with calibrations done in-flight. Horizontal wind speed and direction are calculated following the method outlined in Conley et al. (2014), which combines pitot-static pressure airspeed measurement with GPS-calculated aircraft heading and ground speed. Meteorological parameters were measured using a Vaisala HMP60 probe and geographical coordinates recorded through a Hemisphere high-precision differential GPS. Further descriptions of the aircraft, analyzer precision and accuracy, and met data can be found elsewhere (Conley et al., 2017; Karion et al., 2015; Peischl et al., 2016; Ravikumar et al., 2024; Smith et al., 2015).