A plan approved by South Yorkshire Mayoral Combined Authority (Symca) means an outline business case has been upgraded to full status now funding has been agreed.
The combined local authorities want to lease the airport from its owners, Peel Group, which has refused to sell it despite closing it in October 2022.
The authorities propose a 10-year plan for the site, which will include a focus on sustainable aviation.
South Yorkshire’s mayor Oliver Coppard said: “We have taken the unanimous decision to move the plan for South Yorkshire Airport City and reopening DSA, from outline business case to full business case.”