Flower may transport people (9)
I believe the answer is:
carnation
'flower' is the definition.
(carnation is a kind of flower)
'transport people' is the wordplay.
'transport' becomes 'car' (car is a method of transport).
'people' becomes 'nation' ().
'car'+'nation'='CARNATION'
'may' acts as a link.
(Other definitions for carnation that I've seen before include "Flower like pink" , "Pink - garden flower" , "Oscar Wilde wore a green one" , "Anoint car with the strange flower" , "Showy flower" .)