I agree that there are probably too many airports chasing scheduled passenger traffic in much of the UK. However, it's quite difficult to decide which airports are surplus to requirements, particularly for the future, given the changing nature of both the airline industry and the demographics of the UK.
In 1994, Liverpool had a total of 439,279 passengers, while Durham Tees Valley had 356,380 passengers.
In 2009, Liverpool had a total of 4,879,468 passengers while Durham Tees Valley had 288,298 passengers.
It should be remembered that in the 1980s and early 1990s, that both Liverpool and Teesside had a big population base and considerable economic problems. How would a planner in 1994 known what would happen 15 years later ?
If airport management can keep going financially, who are we to say they should close ?