Birmingham's spent £33m on extending their runway 400m. I've added 750m or so to the Church Fenton runway so based on the BHX spend. that's going to be £50m to £60m just on that cost. Where do we start on the other facilities?
As already stated this project is a non starter in current political/legislative climate.
However Birmingham's 'cost to extend' is much greater than and a putative Church Fenton International. Extension there (like at LBA in eighties) involved putting a trunk road into underpass.