When the Society asked me to give a short introductory paper on overall costs at a meeting where the emphasis will be mainly concerned with financial aspects of aircraft and airports, I felt it might be of some interest to you in the short time I have available to discuss overall costs in terms of urban transport systems. My reasons for thinking this are that for air trips between European cities and particularly within the UK, the convenience or otherwise that a passenger experiences in getting from his home, for example, to the airport and again from the airport at the end of his journey to his point of business, depends largely on the urban transport situation and as you will all know it is a very significant factor in the competition between land based modes and air based modes.