Just as they were during the first three years after Israel quit Lebanon in May 2000, Israeli overflights of its northern neighbor now threaten to become the main point of Israel-Hezbollah friction. During the last round, however, Hezbollah had no weapons capable of truly threatening Israel's planes. This time, aided by Iran and Syria, it seems to be aiming much higher.

Israel deems the overflights essential for intelligence purposes. While it halted them when it first left Lebanon, it resumed them five months later, after Hezbollah kidnapped three Israeli soldiers, and never stopped them again. It was these flights, for instance, that enabled Israel to learn the positions of the long-range missiles that it destroyed on the first day of the Second Lebanon War in 2006. They presumably also provide clues to developments in Syria.

For Hezbollah, the flights were a threat, but also an opportunity: They provided a pretext for continuing its "resistance to the Israeli occupation." It continued its anti-aircraft fire until summer 2003, when one such barrage killed a child in Shlomi, and Israel's fierce retaliatory bombardment caused the organization to desist.

Now, however, it seems keen to reopen this front, even at the cost of provoking a harsh Israeli response.

The aerial front was Hezbollah's principal weak spot during the Second Lebanon War. Israel's air force did as it pleased in Lebanon's skies, from destroying the Fajr missiles to dropping special forces in Hezbollah's stronghold of Bekaa. Now, according to both Military Intelligence assessments and recent reports in the Arabic media, Hezbollah is seeking to close this gap.

Should Hezbollah install advanced anti-aircraft batteries, accompanied by modern radar, this would cause significant problems for Israeli overflights. And that in turn would score domestic points for the organization, justifying its refusal to disarm. Smuggling in such batteries should not be difficult, given the massive quantities of rockets and antitank missiles it has already succeeded in bringing in from Syria.

Which missiles in particular Israel is worried about has not been publicized. But in 2005, when Russia was reportedly about to sell SA-18 missiles to Syria, Israel protested vehemently, on the grounds that such missiles can easily be removed from their carriers, making them highly suitable for use by terrorist organizations such as Hezbollah.