On Monday 27 November by 1030 AEDT, DPS had closed due to ongoing volcanic activity of Mt Agung so all GA flights are cancelled. The far smaller neighbouring LOK airport is also supposedly closed, though I just observed a Citilink flight that appeared to have taken off at about 1300 hours Sydney time. There is plenty of information on the Internet so I won't duplicate that here.
Suffice to say that GA (and competitors) will review the situation tonight, so it is very fluid.
This must cost airlines a lot of money as with passenger numbers building at either end - especially so given many schools or universities have broken up for the 2017 scholastic year and so holidays are uppermost in minds - relief flights will have to eventually be operated, although perhaps GA, as a smaller operator may try to rebook passengers on other airlines such as SQ via SIN.
This could be challenging as we move into December given it is (for outbound travel from Oz) a peak travel month.