One of the abiding memories (iirc!) I have from that series was the reservations room. The status of the flights was written up on a blackboard (sorry chalkboard!) at the front of what was clearly an enormous classroom type building. It had obviously been expanded over time to accommodate more staff, and those at the back were equipped with opera glasses, so that they could read the flight status on the board, and hopefully pass on the correct information to the enquiring passenger!