Israel attacked the base with surface-to-surface missiles from within its territory rather than expose a strike plane to Russian and Russian-made anti-aircraft systems
Israeli military struck a Syrian airbase near Damascus overnight. Israel has struck at targets inside Syria before, ostensibly to thwart weapons shipments to Hezbollah.
Since Hezbollah's intervention in the Syrian conflict in 2013 the group has greatly increased its strength to the point it now even operates a full armored battalion. Despite that Israel has never waged a comprehensive effort to degrade Hezbollah's capabilities in Syria but limited itself to sporadic strikes that do little except register its displeasure with the growing strength of its enemy. (And its reserving the right to strike Syrian territory any time it pleases.)
In other words the value and meaning of its strikes inside Syrian territory is more political than actual.
اندلاع ألسنة اللهب من محيط مطار المزة بعد عدة انفجارات متتالية في المنطقة
Rockets strike at Mezzeh Military airport in Damascus minutes ago pic.twitter.com/kTuobQ4nQT— Hadi Albahra (@hadialbahra)January 12, 2017
It is possible Israel struck now as a sort of reminder to the Israel-friendly Trump administration that Israel has what it believes are its own very important interests in Syria.
The most interesting aspect of the strike however is how it was conducted. Instead of bombing the military airfield from the air, Israel launched surface-to-surface missiles against it.
Syrian news agency SANA reported the strike caused no deaths or injuries. Israel as per its policy refused to confirm it had carried out the strike.