'Effective' was an Allied unrealised plan for the employment of airborne forces for the seizure of objectives in the Schwarzwald (Black Forest) region of Germany, most notably the airfields of the Bisingen area, by units of Lieutenant General Lewis H. Brereton’s Allied 1^st Airborne Army in front of Lieutenant General Alexander M. Patch’s US 7^th Army (spring 1945).

The object of the scheme, which was rendered largely superfluous by the speed of the Allied advance to the east, was to aid the push by Lieutenant General Jacob L. Devers’s Allied 6^th Army Group through SS-Oberstgruppenführer und Generaloberst der Waffen-SS Paul Hausser’s Heeresgruppe 'G' into southern Germany and, most specifically, for the capture of Munich.

'Effective' was also conceived to further the 'Alsos' mission’s task of locating and seizing German nuclear research and personnel in the area, and to prevent their discovery by the advancing French forces. The plan thus called for Major General Elbridge G. Chapman’s US 13^th Airborne Division to occupy the area to forestall its capture by the French, and to seize an airfield that could be used to fly in an 'Alsos' mission team, and later to extract it together with captured German scientists. 'Effective' was scheduled for 22 April, and meanwhile Devers took steps to delay the French advance.

The 'Alsos' mission had learned that the uranium ores that had been taken from Belgium in 1944 had been shipped to the Wirtschaftliche Forschungsgesellschaft plant in Stassfurt, which Major General Robert C. Macon’s US 83^rd Division captured on 15 April. As it was in the occupation zone allocated to the USSR at the 'Argonaut' conference in Yalta, the 'Alsos' mission, led by Pash and accompanied by Lansdale, Perrin and Air Commodore Sir Charles Hambro (head of the British 'raw materials mission'), arrived on 17 April to remove anything of interest. In the following 10 days, 260 truckloads of uranium ore, sodium uranate and ferro-uranium weighing about 1,000 tons, were taken away by a US truck company. The uranium was taken to Hildesheim and most of it was flown to the UK in RAF aircraft; the rest had to be moved to Antwerp by train and loaded onto a ship for delivery to England.

On 20 April, the French 1ère Armée captured an intact bridge over the Neckar river at Horb and seized a bridgehead. It was then decided to send in a ground force rather than the airborne force planned in 'Effective', which was cancelled on 19 April.