Muammar Gaddafi is beginning to use his air power to some effect. Will it help hm defeat the rebels? That depends. Air power is decisive in land combat provided he can use it at certain times and places to isolate sections of the battlefield, allowing his ground forces to attain an overwhelming advantage and so defeat the rebels in detail. Air power can also be used to protect his lines of supply while degrading those of the rebels.
If he instead uses air power independently of his ground forces, the rebels may yet prevail. The rebels need either their own planes, or the capability to deny air power to Gaddafi. The longer Gaddafi holds out, the poorer the rebels chances become.