From Frontiers of Technology (Marshall Cavendish, 1983)...
Airlines have booking offices in every big city. Within minutes, a booking agent can confirm a flight, reserve a seat on the plane and confirm a ticket! There's no fuss, no long form to fill in ... the agent just presses a few buttons. What's the secret?
It's all done by computer
An airline's bookings are stored by computer. Each booking office is linked to the airline's computer, which may be anywhere. For example, British Airways offices the world over deal with their computer at London's Heathrow Airport, and British Caledonian offices deal with a computer that happens to be in Los Angeles!
The visual display unit
Messages sent to the computer and its replies show up on this TV-type screen. The VDU can find out what flights there are, take bookings, list fares, or send special instructions about what the passenger wants, such as vegetarian meals. It can even arrange an entire round the world trip complete with hotel reservations.