Air Antique are trying to flog their classic flight (or were) - maybe this is a convenient excuse for grounding increasingly expensive DC3s.
Air Atlantique have said that after July 16 (when the latest EU-OPS regs take affect) their DC3s will continue to fly on other aerial work such as survey flights and air displays. That doesn't sound like they are looking for an excuse to ground the aircraft.
Their problem is the cost and impracticality of installing certain items of equipment required to permit affected aircraft to continue carrying fare paying passengers on pleasure flights.