Four Palestinians were wounded in the raids, paramedics said. The wounded are reported to be three police officers and a baby who was hit in the face by shrapnel.
A military statement said aircraft attacked eight roads and a bridge leading to sites used for launching home-made rockets and mortar shells.
The attacks on the key bridges cut roads off for thousands of people.
"The objective of targeting them is to prevent the passage of terrorists to reach the areas from which they launch rockets into Israel," the statement said.
An explosion in the southern Gaza Strip killed a fighter on Saturday as he returned from firing rockets into Israel, according to Palestinian security sources. Three people were wounded in the blast.
Palestinian officials identified the man killed as Khalid Abu Sitta, 24, from the Abu al-Rish Brigades, a small, armed offshoot of Fatah.
A spokesman for the group, who goes by the name Abu Harun, said the explosion was caused by an Israeli attack. Witnesses said an Israeli aircraft had fired a missile at the car.
But the Israeli army, which often acknowledges when it carries out such attacks, denied involvement. It said that the explosion appeared to have centred on the car boot, not the engine, where heat-guided Israeli missiles usually hit.
It is not uncommon for Palestinian fighters to be killed when their unstable, homemade explosives detonate accidentally.
Amid the violence, low-flying Israeli air force F-16s carried out mock air raids for a third consecutive day during dawn prayers in Gaza City.
Aljazeera.net's correspondent in Gaza said the sonic booms from the planes shake buildings, shatter windows and strike fear into residents.