I am wondering about the best way to interpolate airborne geophysical data (such as geomagnetic data) with ArcGIS tools (Spatial Analyst, Geostatistical Analyst) to create a surface / grid. The data are huge (millions) and taken along parallel flight lines; each measurement is only a few meters apart, while the distance between the flight lines is about 2 km. Oasis Montaj uses a method called “bi-directional gridding”, but I would prefer using ArcGIS and could not find a similar algorithm. I tested a few and so far, best results were with Natural Neighbors; however, this method seems to have severe limitations regarding the number of input points; already after running it on 2 or 3 million points it takes very long time or does not produce any output at all. Any idea what alternative could be used?