This week at home I've been parsing through some flight data I acquired, looking for a good way to generate heat maps for where planes fly. I thought of a few elaborate ways to do this, but in the end, I just ran a chunk of 10k flights through a simple xy plotter in matplotlib using a low alpha (transparency) value. It's interesting to see the flight corridors emerge as you throw more data at it. The below is about half of the data for a single day.
I've now posted the plotting code in github, under my airline-plotters project: github:airline-plotters