Raven,
I'm aware of the chemical background of Portreath thus why perhaps ideal for a commercial development rather than perhaps a housing development!
Hear what you say about St. Mawgan regarding hangarage & Freight but just look at the location of the hangars to the pax terminal, if you were starting from scratch would you not put them next door to each other?
The railway, indeed any public transport, features in any airport development & growth. When they rebuilt Stansted they put a railway line & station in and let's face it, holidaymakers flying to NQY are leaving their cars at home, costs of taxi's etc. may persuade them that it's cheaper to take the car than to fly.
Changing the subject slightly, I can recall the days of when jetfoils operated from Ramsgate to Ostend, 90 minutes compared to 4+ hours by ship but the punters destination wasn't Ostend, in the same complex as Ostend harbour was the train station and it was an optimum route for getting to the continent.
NQY is trying to attract punters destination Cornwall, not necessarily destination Newquay, thus there need to be public transport connections.
PF