Best time to arrive at Okinawa (Naha) Airport before domestic flight?

We have a flight that leaves from Okinawa (Naha) Airport at 7:05pm to go to Tokyo.

We might end up going Tokashi Island on this day and return at the port at 4:40pm. I believe we will arrive at our car rental place like 5:10pm and there isn't much for them to check as we paid for 100% collision damage waiver.

If we arrive at the Airport at 5:30pm (with suitcase to check-in) is this still plenty of time? If we somehow get delays with returning car etc and we get there at 6pm. Would this still be enough time? Obviously we will try aim for 5:30pm, but in worse case 6pm. Do you guys think we have plenty of time to catch our flight?

by Stunning_Suit_3934