Syrian opposition launched Grad rockets at Aleppo's Nairab airbase on Friday, according to the UK-based monitoring group, Syrian Observatory for Human Rights (SOHR).
The bombardment aimed to break the siege in areas in the city being attacked by regime forces.
A number of armed opposition groups are participating in the new offensive and the bombardment of the airbase was part of the operation, Zakaria Malahifji, an official from the opposition group said.
"Today is supposed to be the launch of the battle," Malahifji said, adding that, "All the rebel groups will participate."
Locations around the Khmeimim airbase near Latakia were also struck by the opposition using a truck-mounted multiple rocket launcher, SOHR said.
The observatory group also reported that more than 15 civilians killed and 100 wounded by opposition shelling on west Aleppo.
More than 400,000 people have been killed in Syria since the civil war started in 2011 and tens of millions displaced.
The war between the Assad regime and opposition forces began after the Arab Spring movement that swept through many countries in the Middle-East and North Africa.