JJflyer -
Once an airport is closed and it's taxyways, [snip] the airport is gone and will not come back without a gargantuan investment.
exactly. When people ask me why I think CYTZ should be retained, I mention that if the land was green space I would never consider building an airport there, but it isn't - the land contains an asset which would take tens if not hundreds of millions to construct from scratch, and which if used properly could be one arm of a strategy to defer the pillaging of prime agricultural land in Pickering (a reliever airport proposed for northeast of Toronto).