Maybe it is a KC-130 tanker variant supporting deployment of the fighters.
I am going to take a guess it is in the Florida area.
UK Royal Navy is in port with their new carrier so it might be picking up the new F-35s.
Royal navy ship is in Jacksonville so it does seem odd for them to be in GNV as it is a bit off route if they are Brits.
I can find no indications of airshows that might account for it either.