Isn't Dundee a small town of continuous decreasing population where the main 'industry' is Social Services, poor students and Ninewells hosp - why would anybody invest ?.
The population of Dundee, in line with the whole of Scotland, is decreasing. This is clearly not something unique to the city. If this is a problem for Dundee to attract airlines then so it should be for every other Scottish airport, which doesn't seem to be the case.
No, the main 'industry' is not social services, no more than it is in any other significant city.
"Poor students" have in Dundee Uni (voted Scotlands top university) and Abertay, massive amounts of continued investment and improvements to enjoy. It creates jobs, benefits the whole city and the students it helps to attract bring significant amounts of money into the local economy.
Ninewells Hospital is a fine teaching hospital, one of the best in Scotland and the UK as a whole and again has a similar impact as the universities.