Turkey is now fighting Isis street by street in the latest embattled city. The reason Turkey hasn't gone into Syria to attack ISIS is because they have asked the U.S. to put in place a no fly zone to protect the Turkish army against airstrikes by Syrian forces and so far the U.S.has refused the request, as late as last weekend the Turkish Government requested the No Fly Zone be put in place.. The Syrian Government has told everybody concerned that any incursion without their compliance will be treated as an aggressive act, but they have also said they are willing to allow attacks on Isis when requested. As Turkey and Syria are not friendly the Turkish Government does not want to risk its ground forces out in the open.
As you can imagine the Turkish Airforce is pretty much non existent. Isis will not have it all their own way now they are fighting the Turks street by street.
