'Trio' (ii) was the British bombing of the Skoda armaments factories at Pilsen in German-occupied Czechoslovakia by Air Chief Marshal Sir Arthur Harris’s RAF Bomber Command (16 April/14 May 1943).

Replacing 'Duet', 'Trio' (ii) involved two raids. The first, on 16/17 April, used 327 aircraft (197 Avro Lancaster and 130 Handley Page Halifax four-engined heavy bombers), of 18 Lancaster and 18 Halifax machines were lost, representing 11% of the aircraft despatched. The raid took place under a full moon and was not successful. In a complicated plan, the Main Force was ordered to confirm the position of the Skoda factory visually with the markers of the Pathfinder Force aircraft intended only as a general guide. In the event, a large asylum building 7 miles (11.25 km) away was mistaken for the factory and only six crews brought back bombing photographs which were within 3 miles (4.8 km) of the real target. The Skoda factory was not hit, but one report says that 200 German soldiers were killed when their barracks near the asylum were bombed.

On 13/14 May 156 Lancaster and 12 Halifax bombers were despatched in another attempt to bomb the Skoda factory: 120 of the aircraft were provided by Air Vice Marshal E. A. B. Rice’s No. 5 Group, and the others were Pathfinder Force aircraft of Air Vice Marshal D. C. T. Bennett’s No. 8 Group. Nine aircraft were lost. The target again proved to be difficult to find and mark accurately, and nearly all the bombs fell in open country to the north of the Skoda factory.