The 2-D barcodes found on boarding passes encode a large amount of interesting flight and passenger data. I wrote a parser to process the output from a scan of a boarding pass barcode.
Technical Details
The boarding pass parser is written as part of Flight Historian, a Ruby on Rails application.
Boarding pass barcodes are in International Air Transport Association (IATA) Bar-Coded Boarding Pass (BCBP) format—a compact text string which can contain details for one or more flights for a given passenger.
The implemented code is located in the BoardingPass class in my bogardpd/flight_log project.