Lufthansa said its decision applies also to its subsidiaries Germanwings, Austrian Airlines, Swiss and Brussels Airlines. In all, 20 flights from Frankfurt, Berlin, Munich, Zurich, Vienna and Brussels were cancelled for Thursday.
The airline initially had suspended flights for 36 hours through the end of Wednesday. Those cancelations were extended because "at the current time there is no sufficiently reliable new information that would justify a resumption of air operations," Lufthansa said.
Air Berlin said it is continuing to evaluate the situation to determine whether further cancelations are necessary.
KLM, Alitalia and Scandinavian Airlines were among other European airlines that also canceled flights Tuesday and Wednesday. Polish airline LOT said it would suspend flights to Israel until the end of July 28.
British Airways, however, said Wednesday it hasn't canceled any of its twice-a-day Tel Aviv flights and had no immediate plans to do so.
A spokesman stressed that British Airways wouldn't fly to Israel if it thought it was unsafe, adding that "each airline draws its own conclusion" on safety.
Aviation security expert Chris Yates said British Airways would have assessed the situation with input from the intelligence services and ultimately concluded there was an acceptable level of risk. He said this may be because the rockets from Gaza "are fairly rudimentary and can't be targeted easily at planes in flight."
Yates said other airlines might have cancelled flights fearing the possibility that rockets could strike their plane on approach or take off, but that Israel's Iron Dome defense system makes that very unlikely.