Not sure that shorting has that much affect on
VB rather than investor confidence in the product. The shares seem to drop when oil rises more than any other factor as LCCs are vulnerable to this. QF has proven their oil hedging successfull in the profit release and REXs' floating fuel surcharge nulified the effect of oil, these stocks have fallen but generally stayed where they dropped to a while back.
VB being hit with poor hedging and dropping load factors and resulting large cut in profits/increasing debt (whatever the cause) does not inspire prospective investors. This poor confidence continues until something changes such as management showing some restraint in a potential recession or the economy/financial sector turns the corner and shows dramatic stable improvement.