Even though Syrian rebels have seized a number of the border crossings with neighboring Turkey, the Turkish government is apparently not done escalating their own border tensions wit the regime, deploying a number of batteries of surface-to-air missiles to the Syrian border today.
This follows several rounds of deploying additional troops and tanks to the Syria-Turkish border, following the downing of a Turkish warplane. Turkey has scrambled warplanes along the border several times since then as well.
The deployment of the missile batteries could be a serious complication for the Syrian military, which will presumably have to employ air power to try to reclaim the lost border outposts from the rebel fighters.
Of course, there is no guarantee that Turkey would automatically attack Syrian warplanes that were involved in their own civil war along the border, but with Turkish leaders openly backing the rebels the possibility cannot be entirely dismissed, which may dissuade Syria from launching such operations in the first place.