I played with visualisation possibilities for BA's all 744 flights over a, say, a month, based on ftbashboard.net data. Two samples from about a month ago are here:

• Interactive version, but VML and therefore only for Internet Explorer. Point at any box, and that destination gets a darker colour across the chart
• Snapshot version (GIF) of the above for all browsers, highlighting IAH flights in this particular example

A quick look at the chart should give a visual impression on the overall E: lots of white space translates into a low E. Departure and arrival times from/to LHR are real data, flight times (ie lengths of the bars) are taken from the timetables.

Some of this may become permanent features on ftdashboard.net later on.