[D13Fd]

Travel websites actually do use certain shared back-end systems in some cases:

https://en.wikipedia.org/wiki/Global_distribution_system

[isbvhodnvemrwvn]

And these systems are ancient, think using-proprietary-keyboard-typing-commands-on-a-terminal ancient - and often the only access control is knowing the last name of the traveler, or an 6-8 character password.

[losvedir]

Aha! Very cool, thanks for sharing that.