From FinnegansWiki
- castles in the air: imaginary or unrealistic plans
- cashel: (Anglo-Irish) castle, ring fort, stone fort
- caiseal: (Irish) castle
- The Castle: Dublin Castle, the centre of British rule in Ireland
- A Finnegans Wake Gazetteer
- Cashel: a town in County Tipperary; formerly the royal seat of the kings of Munster
- kaszel: (Polish) cough
- clashes → anagram of cashels → see line 1
- aired and ventilated: opinions are aired and ventilated in Parliament
- Also, if you unroof a castle, destroying it, it gets "aired and ventilated"
- heard
- vent: (archaic) to utter, to publish
- ventilate: (slang) to shoot with a gun; (of a bullet) to make a hole
