This link to a report for a Darlington Council Cabinet meeting on 6th December 2011 might just clarify some, or all, of the comments made by Skyman771 above.
I'll leave you to do the maths.
http://www.darlington.gov.uk/PublicM...20Item%201.pdf
(If the link doesn't work for any reason go to the Darlington BC website and type Durham Tees Valley Airport into the search box)