Originally Posted by
craz
which was exactly my point. If the OP or anyone else wants to go between 2 countrys within the EU dont fly there via a 3rd country which isnt in the EU or the schengen area
It's not useful to mention the EU in this context, it has little relevance here: to be absolutely clear: don't fly via a non-Schengen country between any 2 Schengen countries, if you only have a single entry Schengen Visa.
(Switzerland is in Schengen but not EU, you won't cross the Schengen borders flying via Switzerland. The UK and Ireland are in the EU but not Schengen, you would cross the Schengen border if flying via the UK or Ireland.)