BoardingBarcode

Allows you to create any board pass barcode using a simple web interface:

###https://shooshx.github.io/BoardingBarcode

With this you can do what this guy does here:
http://gizmodo.com/hacker-builds-a-qr-code-generator-that-lets-him-into-fa-1784884083

This software was created using freely available resources.

This tool is intended for educational purposes only, use at your own personal risk.

Aztec barcode

https://en.wikipedia.org/wiki/Aztec_Code
https://github.com/zint/zint

BCBP standard (the data that goes into a boarding pass)

http://www.iata.org/whatwedo/stb/documents/bcbp_implementation_guidev4_jun2009.pdf
https://shaun.net/whats-contained-in-a-boarding-pass-barcode/

Other useful info

Airline codes
http://www.airlineandairportlinks.com/frameset_linecode.html
International Air Transport Association airport code
http://www.airportcodes.org/