Air Operations, Aleutians

22 343rd Fighter Group P-38s and 37 P-40s mount 9 separate attacks against Kiska. Several of the P-38s are flown by visiting RCAF pilots.

Air Operations, CBI

• 23d Fighter Group P-40s attack a supply dump near Tengchung.

Air Operations, Europe

• 12 Venturas attack shipping and dock installations at Dieppe without a loss.

• 173 Lancasters and 5 Halifaxes are sent to bomb the dockyard at La Spezia. The center of the bombing is northwest of the aiming point. The main railway station and many public buildings are hit, however. 8 other Lancasters lay mines off La Spezia harbor.
• 1 Lancaster is lost.

• 10 Stirlings lay mines in southern Biscay and there are 5 OTU sorties.

Air Operations, Mediterranean

• Beginning about 1750 hours, at least 61 Ju-52s and 15 Bf-109s are downed over the Gulf of Tunis by 12 RAF Spitfires and 46 P-40s from the IX Fighter Command's 57th Fighter Group and an attached squadron of the 324th Fighter Group.
• 6 P-40s and 1 Spitfire are lost

Air Operations, Pacific

An aircraft carrying the Commander of the Japanese Combined Fleet, Adm Yamamoto, is shot down by P-38 Lightning fighters over Bougainville. Yamamoto is killed. The operation is only possible because of the interception of a coded message announcing a visit by Yamamoto.

The decision to try to intercept his plane goes to the highest level. It is surprising the Japanese do not consider the possibility that the code was compromised, for this is another instance of clear intelligence data being used by the Allied forces. No effort is made to change the code. In fact the Japanese do not deduce that their codes are insecure so the risk is worthwhile. As well as suffering the loss of their leading strategist, the Japanese national morale suffers when the death is announced in May. The Americans, of course, make no announcement, since this would obviously suggest to the Japanese how they got the information that Yamamoto was aboard that particular plane. Technically it has been a very difficult well performed mission.

April 18, 1943. P-38 pilots from Henderson Field, Guadalcanal, intercept and shoot down two Mitsubishi bombers over Bougainville.

US P-38

Air Operations, Sardinia

NASAF B-25s attack the Alghero/Fertilla Airdrome and shipping at Porto Torres.

Air Operations, Sicily

• 75 NASAF B-17s attack a marshalling yard at Palermo and the Bocca di Falco Airdrome.
• IX Bomber Command B-24s attack Catania.

Air Operations, Solomons

In a perfectly executed ambush requiring split-second timing, 16 P-38 pilots from the 347th Fighter Group’s 339th Fighter Squadron down 2 G4M 'Betty' bombers and 3 A6M Zeros over southern Bougainville Island. On the flight deck of one of the 'Bettys' is Adm Isoroku Yamamoto, Commander-in-Chief of the Japanese Navy’s Combined Fleet, who is killed. 1 P-38 is lost with its pilot.

Air Operations, Tunisia

• 9th Air Force fighters attack a variety of tactical ground targets throughout Axis-held Tunisia.
• IX Bomber Command B-25s attack several Axis landing grounds.

Axis Diplomacy

A trade agreement between Turkey and Germany is signed.

Battle of the Atlantic

U-123 sinks the British submarine P-615 100 miles southwest of Freetown with the loss of all 44 of her crew. The British submarine was en route to the South Atlantic Command to provide anti-submarine escort training.

Diplomatic Relations

The Soviet Government alleges that German allegations of Soviet responsibility for the Katyn massacre is a Gestapo 'frame-up'.

Mediterranean

The British submarine Regent is sunk, probably on a mine, in the Straits of Otranto with the loss of her entire crew of 63.

North Africa

A massive convoy of 100 transport planes leaves Sicily with supplies for the Axis forces, but at least half are shot down by Allied fighters. This action becomes known as the 'Palm Sunday Massacre'. 70 US and British fighters are directed to the proper intercept point from Ultra intercepts. 59 Ju-52 transport planes and 10 escort fighters are shot down by P-40s of the US 9th AAF. 6 P-40s and 3 escorting Spitfires are lost.

Mitchell B-25 bombers fly together in formation on their way to attack German Marshal Rommel's positions in North Africa on April 18, 1943. (AP Photo)

Mitchell B-25 Bombers in Formation

(Air Ops, Medit)In Operation FLAX, Allied planes, which have been conducting an offensive to disrupt the flow of German air transport from Italy and Sicily to Tunisia since April 5th, have a particularly good day, destroying 50-70 of some 100 enemy transport planes and 16 of the escort for the loss of 6 P-40s and a Spitfire. Operation FLAX, while contributing materially to the success of Operation VULCAN - the final ground offensive to clear Tunisia - had been planned originally for February, before VULCAN plans had been formulated. In preparation for VULCAN, other Allied planes intensify efforts against enemy airfields beginning this night.

The British 8th Army releases the 1st Armored Div to the British 1st Army in preparation for VULCAN.

Pacific

The US submarine Drum sinks the Japanese ammunition ship Nisshun Maru (6380t) about 200 miles north-northwest of Mussau Island, Bismarcks. The submarine chaser CH-18 rescues survivors, which include a number of Army prostitutes.

War Crimes

The Russians make an announcement on the Katyn massacre alleging predictably that the Germans have concocted the whole story: 'The hand of the Gestapo can easily be traced in this hideous frame-up.'