Il y eut bel et bien des mines larguées par avion et c'était efficace :voici un bilan côté british origine WIKI mais confirmé par ailleurs

Citation:

In September 1939, the UK announced the placement of extensive defensive minefields in waters surrounding the Home Islands. Offensive aerial mining operations began in April 1940 when 38 mines were laid at each of these locations: the Elbe River, the port of Lübeck and the German naval base at Kiel. In the next 20 months, mines delivered by aircraft sank or damaged 164 Axis ships with the loss of 94 aircraft. By comparison, direct aerial attacks on Axis shipping had sunk or damaged 105 vessels at a cost of 373 aircraft lost. The advantage of aerial mining became clear. The United Kingdom geared up for mining; a total of 48,000 aerial mines were laid by the Royal Air Force (RAF) in the European Theatre during World War II.[16]

Les allemands étaient aussi très actifs

Citation:

In the 1930s, Germany had experimented with the laying of mines by aircraft; it became a crucial element in their overall mining strategy. Aircraft had the advantage of speed, and they would never get caught in their own minefields. German mines held a large 1,000 lb. (450 kg) explosive charge. From April to June 1940, the Luftwaffe laid 1,000 mines in British waters. Soviet ports were mined, as was the Arctic convoy route to Murmansk.[12] The Heinkel He 115 could carry two medium or one large mine while the Heinkel He 59, Dornier Do 18, Junkers Ju 88 and Heinkel He 111 could carry more.

Bien sur,en Manche les vedettes rapides en posaient beaucoup plus peut-être,sans compter toutes celles déposées par les sous-marins de tous les bords,et qui parfois prélevaient leur dîme sur les sous-marins eux mêmes.......

La Kriegsmarine n'était pas préte , elle avait la technologie mais pas le nombre pour faire face , elle ne pouvait donc que combatre et mourir

Bien sûr qu'elle a eu du panache , ce que je voulais dire c'est que vue la disproportion des forces , elle était condannée des le début des hostilités avec certes quelques coups d'éclats mais cela restait " que " quelques coups d'éclats

là je suis tout à fait d'accord avec toi sur le sujet