You can fly to Antalya or Dalaman.
The tour starts in the morning, so it is better to arrive in Fethiye or Kas a day earlier and relax after the journey. The road from Dalaman airport to Fethiye will take 1 hour by public transport, to Kas - 3.5 hours. The road from Antalya Airport to Fethiye takes 4 hours, to Kas - also 4 hours.
Return: the tour ends in the evening. You can fly from Dalaman after 20:00, from Antalya - the next day.