Herein the US Army Air Service later named the Army Air Corps (AAC) aeroplanes developed some capabilities. They could go places! Pilotage-navigation was developed into dead reckoning.  The need for ground and air navigation equipment became ever more apparent as flight time in the air and distances travel increased dramatically. Army McCook Field, at Dayton, Ohio, pilot-navigator engineers, such as Lt Hegenberger, Lt. Frank Lahm, and Lt. Billy Mitchell started to work and solve the problems of air navigation. In 1924 three Army Douglas World cruisers flew around the world. And the US Post Offices conducted across the US flights using the new lighted-rotating beacon airways system for navigation. In mid 1927, a former US Air Mail pilot, Capt. Charles Lindbergh of the Missouri-Army National Guard crossed the Atlantic Ocean solo, navigating by dead reckoning procedures all well worked out on his preflight Mercator projection map. Capt Lindbergh navigated with the aid of an inductor compass, air speed indicator, aircraft bubble levels, and a drift meter. The Army Air Corps developed some eight aircraft types in this period.

Navigator developments in this period:

• Compasses (air compass, hand bearing compass, inductor & aperiodic compass with dead-beat filaments) were improved for aircraft post WW-I Ref. History of Air Navigation by Arthur J. Hughes, Chapter II Air Navigation 1918 published by George Allen & Unwin LTD, London England 1946 and Transatlantic Flight by Joshua Stoff, Dover Publication Inc, NY page 31 (Ryan Company Spirit of Saint Louis, cockpit instrument pane photo). Ref History of Air Navigation by Arthur J. Hughes, published by George Allen & Unwin LTD, Chapter VI Compasses London England 1946. Also the astro-compass was used in the North & South Polar flights by Admiral Byrd, USN. Ref. History of Air Navigation by Arthur J. Hughes, Chapter VI Compasses, published by George Allen & Unwin LTD, London England 1946. Page 117.
  
• Sextants (Countinho bubble sextant by Portuguese Navigator Capt. Jago Countinho and R.A.E. Mark series bubble sextants) improved for aircraft, with the first real air sextant  being the Baker Air Sextant designed by Captain T. Y. Baker, Royal Navy, UK: Ref. History of Air Navigation by Arthur J. Hughes, Chapter III Historic Flights 1919-1930, pages 41-51, published by George Allen & Unwin LTD, London England 1946.
  
• Wimperis drift indictor and airspeed indicators were added to aircraft for longer range flights. Ref. History of Air Navigation, by Arthur J. Hughes, published 1946 by George Allen & Unwin LTD, London England. Page 46.
  
• Two experimental radio directional beacons as navigational aids, one at the starting point and the other at the Hawaiian destination were set-up to be used by the Army Air Services Material Division Fokker C-2 Bird of Paradise  trans Pacific flight crew, navigated by Lt. A.E. Hegenberger, flying Oakland California to Hawaii, 25hours & 50 minutes, September, 1927. Ref. Splendid Vision, Unswerving Purpose: by HO/ASC AFMC, AFHMP, USAF, W-P AFB, Ohio. Pages 145 & 146.
  
• Transcontinental-beacon lights (most electrical and some calcium carbide gas generator types) were set-up approximately every 50 miles across the USA, establishing the civil airways for night flight navigation, circa 1926. This system was established by the US Post Office and flown by all weather pilots like Charles Lindbergh. Ref. This was Air Travel by Henry R. Palmer Jr., published by Bonanza Books, NY NY, 1960. Page 125 and We, by Charles Lindbergh, published 1927.