sentences:  The Balloon Companies were disbanded in 1911 and were reformed as the Air Battalion of the Royal Engineers, forerunner of the Royal Air Force.Alexander Graham Bell developed a tetrahedral kite, constructed of sticks arranged in a honeycomb of triangular sections, called cells.From a one cell model at the beginning of the 1890s, Bell advanced to a 3,393 cell "Cygnet" model in the early 1900s.