Dr Keith Thomas very kindly did some research for me on the web and came 
   up with the following information:
   
        Jever airfield was four Kilometres south of Jever town [ 53.52 N 07.53E] 
   and 7 metres [ 24 feet above sea level]. The airfield was started in 1935 and
   became operational in 1936 with Coastal Fighter Group 136 flying He 51's and 
   later Ju 87b, but its contact with the RAF came after the Polish incursion and 
   they brought back Messerschmitt Bf 110's and 109's.
   
        It was from Jever that Wolfgang Flack flew his BF110'c Zerstörer taking
   out the Wellingtons  heading for Bremen, he didn't get it all his own way and 
   came down on Wangerooge.  Why mention him?  The quote is that he was the most 
   influential Luftwaffe officer of the World War 2 ...there is a book about him 
   and he went on to be a night fighter.  He wasn't long at Jever.
   
        The airfield was literally carved out of the surrounding forest.  The local 
   rumours claimed that, as it was only a grass airfield during the war, it was 
   very difficult to recognise from the air and that it was never bombed or even 
   discovered by the RAF.    
 
        Keith says he had the same information as me that suggested that the 
   airfield was handed over intact at the end of the conflict, it was not apparently 
   recognised for what it was but Keith's next door neighbour in Beethoven Strasse
   was Vic Azzaro and he recollected being attacked while flying over Jever.    

        Translation from the German introduction to the RAF Jever Open Day 6th June 
   1959 by Air Chief Marshal Sir Humphrey Edwardes Jones KCB; CBE; DFC; AFC; RAF
   Commander-in-Chief, 2nd Tactical Air Force (Germany):

        "An airfield for light recreational aircraft from the middle of the 
   1920s to 1935, an operating base for the Luftwaffe from 1935 to 1945 and today, 
   a fighter base for the Royal Air Force within the NATO defence system - these 
   are the three development periods of Jever airfield.

        After the first World War the Focke-Wulf Works in Bremen had a small sports
   airfield built on the edge of the Upjever forest.  This was occupied by seven 
   light sporting planes.  The Luftwaffe took the airfield over in 1935 and within 
   a year extended it by felling a large part of the Jever forest to form a fighter 
   base.   Hangars, quarters, a hospital, and underground aviation fuel dump sprang 
   up in quick succession, so that on 1st May 1936 General Mulch was able to hand 
   over the airfield in working order to the 1st Commanding Officer, Hauptmann 
   Melrich.

        In June 1937 Jever airfield was manned by a fighter wing with three 
   squadrons.

        In September 1939, Me 109s and Me 110s were stationed at Jever.  They flew 
   their first sorties against 22 Wellington bombers, which planned an attack on 
   German ships off Schillig and Wilhelmshaven.

        In 1943 additional Ju 52s came to Jever.  These were used as mine detectors.  
   Towards the end of the war the Me 109 and Me 110 fighters were withdrawn from Jever 
   and replaced by Ju 188 night fighters.

        The Luftwaffe had not extended the airfield any further and when the English 
   took it over they used it as an auxiliary base at first.

        Between 1945 and 1951 the airfield was garrisoned by Poles, Canadians, Danes 
   and Jewish immigrants."