| CHAPTER | | PAGE |
| I | What the Newspaper Told | [9] |
| II | In the Offices of the New York Herald | [17] |
| III | Someone Tries to Buy the “Flyer” | [27] |
| IV | Getting the “Flyer” Ready | [33] |
| V | Buck Stewart—and a Warning | [46] |
| VI | Escaping From Deadly Shadows | [54] |
| VII | What Happened to Ned | [62] |
| VIII | Six Miles Up in the Air | [70] |
| IX | Paris Proves Unfriendly | [78] |
| X | An Adventure in the Ardennes | [86] |
| XI | The Fight in the Forest | [95] |
| XII | Buck Takes His Life in His Hands | [100] |
| XIII | “To Be Shot at Sunrise” | [107] |
| XIV | The Rescue | [115] |
| XV | In Deadly Peril | [124] |
| XVI | Ned Saves the “Flyer’s” Crew | [129] |
| XVII | Bob Russell’s Story | [134] |
| XVIII | How Bob Was Captured as a Spy | [142] |
| XIX | A Strange Country | [149] |
| XX | A Fight With Wild Cossacks in Poland | [157] |
| XXI | Inside of Besieged Przemysl | [165] |
| XXII | The Boys Perform an Act of Mercy | [173] |
| XXIII | Strange Sights in Vienna | [182] |
| XXIV | On the Trail of the Conspirators | [191] |
| XXV | The Boys Get Worried Over Ned | [199] |
| XXVI | An Attempt to Assassinate the Emperor | [209] |
| XXVII | The Man in the Cloak Surprises Everybody | [216] |
| XXVIII | Surrounded by German Zeppelins | [225] |
| XXIX | The Battle Above the Clouds | [230] |
| XXX | The Most Terrible Accident of All | [236] |
| XXXI | The End of the “Ocean Flyer” | [244] |