I don't think it would add DCA-ATL, but maybe BOS-ATL and ATL-FLL the day it re-opens ATL.

For BOS-ATL, it'd likely steal traffic from WN/FL. WN doesn't fully convert to all WN metal until late in the year. WN might stick or maybe not, but fi not, just sell connections via BWI the same way that it doesn't compete on RDU-BOS or CLT-BOS but discounts itineries via BWI.

For ATL-FLL, there could be some component of international connections for JetBlue along with O&D and some backtrack itinery sales like maybe DCA-FLL-ATL. Spirit sells ACY-FLL-ATL similarly in Winter. FLL-ATL fares would probably become very competitive with another carrier in the mix, but it might hurt WN sticking around on ATL-PBI if many that would have chosen that opt for the lower fare ATL-FLL.