"Via Amsterdam" is not a clause; it is a prepositional phrase.
Student or Learner
(If not I'd like to know where I went wrong - I am aware that there are many different ways of labelling grammar but I am currently sticking with what I've been taught)
"Are you flying straight back to Manchester?" - Simple interrogative sentence.
"I am going to watch Milan-Rome in the San Siro on Sunday." - Simple declarative sentence.
I'm not sure what kind of a clause, 'via Amsterdam' is?! Ahhhh!
Thank you for your time!
If it is on its own, then it would be a sentence fragment.