"General Ali Mahmud was killed yesterday with two of his bodyguards inside the airport, where fighting is ongoing," Observatory director Rami Abdel Rahman told AFP.
"The rebels have advanced, but they have not yet taken control" of the facility, he added.
Since the beginning of this year, rebel fighters have been trying to seize a string of northern airports, including Aleppo international airport, and the Jarrah, Kwiyres, Minnigh and Nayrab military fields.
Elsewhere, the Observatory reported regime air raids on the Jobar neighbourhood of the capital Damascus and against the rebel-held town of Raqa.
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There were also sporadic air raids against the orchards south of Banias, where the bodies of 62 people were found yesterday after an assault by government forces.
The opposition has said a growing number of reported killings in Syria raises the spectre of a campaign of "ethnic cleansing" in Syria.
Violence throughout the country yesterday left at least 148 people dead, including 40 civilians, 74 rebels and 34 soldiers, the Observatory said.