Preface: This report has been prepared in the M.I.T. Flight Transportation Laboratory under the supervision of Professors R.H. Miller and R.W. Simpson, with contributions from H.A. Fitzhugh, J.F. Fort, R.A. Gallant, G.B. Katz, J.D. O'Doherty, C.H. Pearlman, M.P. Scully, and C.M. Wooten. It forms Part III of a series of reports in a research planning study carried out by the Massachusetts Institute of Technology for the NORTH EAST CORRIDOR TRANSPORTATION PROJECT of the United States Depart ment of Commerce. The authors wish to express their appreciation to the many personnel from airframe and engine manufacturers and the airline operators who contributed so generously of their time and gave access to various detailed information as background for this study. Other reports prepared by M.I.T. under this contract are: Part I. Survey of Technology for High Speed Ground Transport. Part IA. Bibliography of High Speed Ground Transport. Part II. High Priority Research Tasks for High Speed Ground Transport. Part IV. Cost Methodology and Cost Models for High Speed Ground Transport.