Several people on this forum don't seem to understand the reason behind the petition and the envisaged purpose of the airport should the site become one again.
As a Sheffield native and someone who is affected by the local economy let me spell out the attitude that lots of people in the city have which, incidentally, is shared by the Federation of Small Businesses.
Sheffield, the fourth-largest city in the country and the largest city in Europe without its own airport (DSA isn't really Sheffield), is about to lose a piece of tarmac. This piece of tarmac represents the city's only chance to benefit financially from air travel in the future. Sheffield City Airport ultimately wasn't given the opportunity it deserved thanks to executive incompetence (read into that what you will); the site's intact runway represents unfulfilled potential which, without too much difficulty, could be realised.
Nobody thinks that Sheffield City Airport could fulfil a similar function to or be as successful as London City however lots of people find it hard to believe that, quite simply, it couldn't eventually be more beneficial to Sheffield as an airport than another business park would be.
Incase you didn't know there is already a lot of unused office space around here.