Is LH/sub 2/ the high cost option for aircraft fuel

The argument is frequently heard, ''LH/sub 2/ would be a very desirable fuel for aircraft in the post-petroleum era except that it is too expensive and the cost of providing facilities at airports to liquefy, store, and handle it properly is prohibitive. Is LH/sub 2/ really too expensive. Are there no circumstances under which hydrogen can be produced economically so as to be competitive with other alternative fuels. Does the fact that LH/sub 2/-fuelded aircraft are more energy efficient in performing their mission alter the picture. How much will it cost to provide LH/sub 2/ facilities at airports. How many airports will need to be provided with such facilities to constitute a practical operational system for airlines. How could such facilities be funded. This paper examines each of these questions in turn.