Sahar Head El Abbadi, Zhenlin Chen, Philippine M. Burdeau, Jeffrey S. Rutherford, Yuanlei Chen , Zhan Zhang, Evan David Sherwin , Adam R Brandt 

Methane is a major contributor to anthropogenic greenhouse gas emissions. Identifying large sources of methane, particularly from the oil and gas sector, will be essential for mitigating climate change. Aircraft-based methane sensing platforms can rapidly detect and quantify methane point-source emissions across large geographic regions, playing an increasingly important role in industrial methane management and greenhouse gas inventory. We independently evaluate the performance of five major methane-sensing aircraft platforms: Carbon Mapper, GHGSat-AV, Kairos Aerospace, MethaneAIR, and Scientific Aviation. Over a 6-week period, we released metered gas for over 700 single-blind measurements across all five platforms to evaluate their ability to detect and quantify emissions that range from 1  kg(CH4)/hr to over 1,500  kg(CH4)/hr. Aircraft consistently quantified releases above 10  kg(CH4)/hr, and GHGSat-AV and Kairos Aerospace detected emissions below 5 kg(CH4)/hr. Fully-blinded quantification estimates for platforms using spectroscopy-based measurements have parity slopes ranging from 0.76 to 1.13, with R2 values of 0.61 to 0.93; the platform using an in situ measurement approach has a parity slope of 0.5 (R2 = 0.93). Results demonstrate aircraft-based methane sensing has matured since previous studies and is ready for an increasingly important role in environmental policy and regulation.