OpenFlights is OK but the graphics are pretty basic.
I took a look at FlightMemory and it doesn't allow you to do multiple segments (especially domestic/international flights). I plugged in ATL -> MSP and MSP -> YYC and they were displayed on two different maps (one domestic and the other on the world map). This was all one trip. I wanted to show them together.
I know these are two options and they kind of work...but does anyone else have any other good tools? Thanks.