none - Newquay is a very small town with few people in the immediate area
Truro, Plymouth, Exeter etc all have fast train services and few people use the airport - hence the problem in getting & keeping airlines operating from it
The argument about City Centre travel times was to do with access to places like LHR, Schipol etc etc - ie at the other end of the trip .
Cornwall has a population of just over 536,000 spread over 1400 Sq miles - it's just not enough people to support a public-service airport