A Jihad official told AFP that a chief of the Al-Quds Brigades, Imad Yassin, tasked with firing rockets at Israel, was killed and a colleague in the group's armed wing was wounded, the source said.
A missile hit the car in Wadi Gaza village on the southern outskirts of Gaza City, witnesses said.
"Two of the wounded have serious burns and their condition is very serious," said a medical source.
An Israeli army spokeswoman confirmed the air strike targeted "a car between Gaza City and the Deir al-Balah camp carrying an Islamic Jihad cell responsible for the firing of rockets into Israel".
Islamic Jihad has fired dozens of makeshift rockets into neighbouring areas in Israel, causing little damage. According to the Israeli military, about 120 rockets have struck southern Israel over the past week.