Mountain transport being cut back interrupts take-off (3,4)
I believe the answer is:
ski lift
'mountain transport' is the definition.
(transport at a ski resort)
'being cut back interrupts take-off' is the wordplay.
'being' becomes 'life' (life is a kind of being).
'cut back' means to remove the last letter.
'interrupts' means one lot of letters goes inside another.
'take-off' becomes 'skit' (both can mean a send-up or parody).
'life' with its final letter taken off is 'lif'.
'lif' going into 'skit' is 'SKI-LIFT'.
(Other definitions for ski lift that I've seen before include "means of transport" , "Winter sports facility" , "one can ride up here" , "'Conveyance to bring people up snowy mountains (3,4)'" , "Winter sports elevator" .)