Boarding national airline, bully missing first of ballots (9)
I believe the answer is:
electoral
'bully missing first of ballots' is the definition.
Both the answer and definition are adjectives. Perhaps you can see an association between them that I don't see?
'boarding national airline' is the wordplay.
I cannot quite see how this works, but
'national' could be 'elector' (elector is a kind of national) and 'elector' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for electoral that I've seen before include "made up of voters" , "Relating to voters" , "Relating to polls" , "concerning voters" , "Like popular choice" .)