Escape, knocking back lager (4)
I believe the answer is:
slip
'escape' is the definition.
(I know that slip is a type of airplane maneuver)
'knocking back lager' is the wordplay.
'knocking back' is a reversal indicator.
'lager' becomes 'pils' (Pilsner beer).
'pils' written backwards gives 'SLIP'.
(Other definitions for slip that I've seen before include "failure" , "Loose one's footing" , "See 16" , "release > voucher" , "Slide; fielder" .)