QF have cancelled at least 4 CBR-SYD flights this morning. (At least one VA as well).
The screens are saying air congestion in SYD.
Lounge staff also just offered to move me to an earlier flight. 
Staff just gave me new boarding pass (717 instead of dash8 
), said SYD is on 1 runway
They put me on 1502, which was meant to depart before I got to the airport
