In 2012, finding the price of a flight is something I could probably ask my five year old to help with - she'll probably go for my phone and find the Kayak or Hipmunk app icon and tap away. It wouldn't even surprise me if she managed to get close to the results I was looking for.
In 1991, things were different; Airfare came from your travel agent, and you did not have to concern yourself with anything technical. In fact, chances are, your travel agent wouldn't let you anywhere near their cherished green-screen terminal.
The business traveler had different needs, and for them there was the OAG guide
(Official Airline Guide), a large book with the times and prices of almost every flight in the world. In 1991, OAG released their book on a CD-ROM (and delivered the required equipment with it since nobody back then owned a CD-ROM drive).
For the real hardcore users, a version was also released on the Sony DATA Discman, pictured here on the left. Think of this contraption as a very early Amazon Kindle. The unit read data off small CD's in a cartridge, and was the worlds first portable electronic flight guide.
With this in hand, you could call yourself the ultimate frequent flier - and probably find airfare quicker than the local travel agent. OAG CD's for Sony came in the mail every three months, keeping your data up to date with the latest flight times and prices. Sony discontinued the DATA Discman in the late 90's as the technology moved on to PDA's.