One’s driving into the sun: a lift could be the alternative (5)
I believe the answer is:
stair
'a lift could be the alternative' is the definition.
I can't tell whether this defines the answer.
'one's driving into the sun' is the wordplay.
'one's driving' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'into' means one lot of letters goes inside another.
'the sun' becomes 'star' (I've seen this before).
'i' inserted inside 'star' is 'STAIR'.
Can you help me to learn more?
(Other definitions for stair that I've seen before include "this could get one down" , "Bit of a flight!" , "single step in a series" , "one on the way up" , "section of flight" .)