Markieta's blog post outlines his workflow using ArcGIS. It's a bit cumbersome - apart from having to jump through hoops to read the data from the original DAT files, apparently the dataset has to be split into six parts to be able to process it. (For a measly 58K rows?!)
No details are provided about styling, which is the key part of the exercise. The images apparently use alpha blending to show flight density. Also, the coordinate system seems to be more curvaceous than the squaresville Plate Carree I used (so much more haute couture than saying Lat/Long). Both of these are easy to do in JEQL. Here's some samples of the improved output, using the alpha channel and a Mollwiede projection.
Europe
North America
And here's the entire image, in glorious hi-res suitable for framing: