Don't know if it is useful to bump this thread or not, but I did a roundtrip from Oaxaca to Huatulco last week with Aerotucan.

The flight was comfortable and well-operated given the limitations of the aircraft -- it's obviously not Emirates first class, and it's understandable why the baggage limit is only 15 kg/person. Note that all baggage aside from purses/cameras, etc. must be checked as there is no carry-on storage in the cabin.

The airplane (I flew XA-TDS as pictured in JDiver's photo) gets bounced around a bit due to its small size and the mountain air separating Oaxaca from the coast, so it may be tough for sensitive flyers. However, my local friends assure me that it is better than the alternative, a long drive through perilous mountain switchbacks. Each flight was no more than 20 minutes behind schedule.

At both Oaxaca and Huatulco, Aerotucan now uses the main passenger terminal (although the flight does not appear on the departure screens; in Huatulco there is no sign above the check-in counter, but given that there are only a few counters it's not difficult to find the agent in the Aerotucan shirt). If there are other flights departing at the same time, pay attention (in Huatulco, the boarding call almost went unnoticed due to an Interjet A320 boarding at the same time).

The tickets were booked by family locally, so unfortunately I can't speak to credit card acceptance or the best way to reserve.