He asked
'Are they all heading for the City of Edinburgh'?
Of course there not as Edinburgh serves a far wider area than just Edinburgh and as you rightly pointed out that the passengers will be heading all over Socotlsnd.
If you read my reply it was obvious my sarcasm was led by the fact that the question was asked if 13 million passengers 'are heading for the City of Edinburgh' which of course they are not.
It's quite obvious.