1 ▁February ▁ 1 9 1 6 , ▁the ▁en velope ▁lost ▁pressure ▁and ▁the ▁plane ▁was ▁prem ature ly ▁separated ▁from ▁it ▁at ▁ 4 , 0 0 0 ▁feet . ▁Both ▁the ▁officers ▁were ▁killed ▁and ▁there ▁was ▁no ▁further ▁experiment ation ▁with ▁small ▁air ships . ▁ ▁In ▁May ▁ 1 9 1 6 ▁a ▁Br istol ▁Sc out ▁flow n ▁by ▁F lt . ▁L t . ▁M . ▁J . ▁Day ▁was ▁mounted ▁above ▁the ▁top ▁wing ▁of ▁a ▁Por te ▁Baby ▁flying ▁boat ▁flow n ▁by ▁S q n . ▁L dr ▁John ▁Cy ril ▁Por te , ▁and ▁was ▁successfully ▁released ▁at ▁a ▁height ▁of ▁ 1 0 0 0   ft ▁( 3 0 0   m ). ▁Although ▁successful ▁the ▁scheme , ▁intended ▁to ▁provide ▁long - range ▁defence ▁against ▁Ze ppel ins , ▁was ▁not ▁purs ued . ▁ ▁In ▁ 1 9 1 8 ▁the ▁Royal ▁Air ▁Force ▁experiment ed ▁with ▁ ▁launch ing ▁ ▁S op with ▁Cam el ▁f igh ters ▁from ▁H M ▁Air ship ▁ 2 3 . ▁ ▁The ▁Germ ans ▁also ▁experiment ed ▁with ▁the ▁idea , ▁susp ending ▁an ▁Al bat ros   D . III ▁f ighter ▁aer op lane ▁below ▁a ▁Ze ppel in ▁and ▁re le asing ▁it ▁at ▁alt itude : ▁the ▁intention ▁was ▁to ▁use ▁the ▁aer op lane ▁to ▁defend ▁air ships ▁against ▁the ▁British ▁se ap lane ▁pat rol s ▁encountered ▁over ▁the ▁North ▁Sea . ▁Although ▁the