If you're interested in the subject, let me introduce you to GCMap.
GCMap can plot a line between any two IATA airport codes; actually you can put arbitrary number of pairs comma separated; and best of all, they can be passed as a URL param. For example: `JFK-LHR,LHR-CDG,CDG-FRA`
GCMap doesn't have a whole lot of different map projections to choose from. Having more than one pair on a single map will result in a pretty bad map projection. That's my biggest complaint. They really need to add more better projections such as Mollweide, Winkel Tripel, Robinson, etc. Or they should just have a globe.
GCMap can plot a line between any two IATA airport codes; actually you can put arbitrary number of pairs comma separated; and best of all, they can be passed as a URL param. For example: `JFK-LHR,LHR-CDG,CDG-FRA`
http://www.gcmap.com/mapui?P=JFK-LHR,LHR-CDG,CDG-FRA
I track my own flights by sending an email to myself with a GCMap URL every now and then.