EXPERIMENTS WITH PLANES—LILLIENTHAL’S GLIDER—LANGLEY’S AERODROME—SUCCESS OF THE WRIGHTS—FIRST AEROPLANE FLIGHTS. III. WHY AN AEROPLANE FLIES 25 THE HELICOPTER—THE ORNITHOPTER—WING SURFACE—FLYING SPEED—LANDING SPEED—EFFECT OF MOTORS—THE SEAPLANE. IV. LEARNING TO FLY 34 EARLY METHODS—DEVELOPMENT OF SCHOOLS—STUDYING STRUCTURE OF PLANES, MOTORS, THEORY OF FLIGHT, AERODYNAMICS, MAP READING—FRENCH SYSTEM—GOSPORT SYSTEM. V. AEROPLANE DEVELOPMENT, 1903 TO 1918 47 ADER’S EXPERIMENTS—MAXIM’S MULTIPLANE—DUMONT’S AEROPLANE—WRIGHTS’ 1908 PLANE—VOISIN PUSHER—BLERIOT’S MONOPLANE—AVRO TRIPLANE—FARMAN’S AILERONS—OTHER TYPES. VI. DEVELOPMENT OF THE AEROPLANE FOR WAR PURPOSES 67 GERMAN AERIAL PREPAREDNESS—PRIZES GIVEN FOR AERONAUTICS BY VARIOUS GOVERNMENTS—FIRST USE OF PLANES IN WAR—FIRST AIRCRAFT ARMAMENT. VII. DEVELOPMENT OF THE LIBERTY AND OTHER MOTORS 76 DEBATE IN REGARD TO ORIGIN OF LIBERTY MOTOR—LIBERTY-ENGINE CONFERENCE, DESIGN, AND TEST—MAKERS OF PARTS—HISPANO-SUIZA MOTOR—ROLLS-ROYCE—OTHER MOTORS. VIII. GROWTH OF AIRCRAFT MANUFACTURING IN UNITED STATES 94 THE 1912 EXPOSITION—THE FIRST PAN-AMERICAN EXPOSITION—THE MANUFACTURERS AIRCRAFT EXPOSITION—DESCRIPTIONS OF EXHIBITORS—GROWTH OF AIRCRAFT FACTORIES—NAVAL AIRCRAFT FACTORY. IX. THE DEVELOPMENT OF THE AERO MAIL 134 FIRST MAIL CARRIED BY AIRCRAFT—NEW YORK—PHILADELPHIA—WASHINGTON SERVICE—NEW YORK—CLEVELAND—CHICAGO SERVICE—FOREIGN AERO MAIL ROUTES. X. KINDS OF FLYING 151 NIGHT FLYING—FORMATION FLYING—STUNTING—IMMELMAN TURN—NOSE DIVING—TAIL SPINNING—BARREL—FALLING LEAF, ETC. XI. AERIAL NAVIGATION 161 ATMOSPHERIC CONDITIONS—WINDS AND THEIR WAYS—CLOUD FORMATIONS, NAMES, AND ALTITUDES. XII. COMMERCIAL FLYING 169 BUSINESS POSSIBILITIES OF THE AEROPLANE—SOME CELEBRATED AIR RECORDS—GERMANY’S INITIAL ADVANTAGE—A HUGE INVESTMENT—CAUSES OF ACCIDENTS—DISCOMFORTS OVERCOME—INEXPENSIVE FLYABOUTS—THE SPORTS TYPE—ARCTIC-FLIGHT—NO EAST OR WEST. XIII. THE COMMERCIAL ZEPPELIN 203 THE AMBITION OF THE AGES REALIZED—A GIANT GERMAN DIRIGIBLE—ZEPPELIN ACCOMPLISHMENTS—HIGH COST OF ZEPPELINS—SAFETY OF TRAVEL—SOME BRITISH PREDICTIONS—THE FUTURE OF HELIUM—THE LIFE-BLOOD OF COMMERCE. XIV. THE REGULATION OF AIR TRAFFIC 235 IMPORTANCE OF SAME—LAWS FORMED BY BRITISH AERIAL TRANSPORT COMMITTEE LIKELY TO BE BASES OF INTERNATIONAL AERIAL LAWS—COPY OF SAME. XV. THE TRANS-ATLANTIC FLIGHT 251 THE NC’S—THE LOSS OF THE C-5—READ’S STORY—BELLINGER’S STORY—THE GREAT NAVAL FLIGHT—HAWKER’S STORY—ALCOCK’S STORY—TO AND FROM AMERICA—THE R-34. APPENDIX I 327 UNITED STATES AIRCRAFT AND ENGINE PRODUCTION FOR THE UNITED STATES AIR SERVICE. APPENDIX II 354