Unlike May and June 1941, Malta was not a factor in the war in North Africa in May 1942. A few Wellingtons still operated from Malta, but they were only able to make sixty sorties against Tripoli during the "lull" in the fighting. They did have a few successes while raiding Palermo, Sicily, sinking or damaging ships.
Only Liberators from Egypt could now hit Tripoli, and they only arrived in numbers by May 1942. Because of that, the main successes against Axis shipping were achieved by raiding Benghazi, due to the closeness of Desert air fields. Bombers operating around the clock made 741 sorties against the port and installations at Benghazi from February to May. As the enemy showed signs of an imminent land attack, Kittyhawks and Bostons appeared over Benghazi during daylight. The attacks seemed to not seriously interrupt the supply buildup, however. This is based on the account in Vol.III of the Official History.