Just FYI I took an 8 day trip to Cozumel last month (June '18) and flew RT from Denver directly to Cozumel on American. Thru Dallas on the outbound and thru Miami on the way back. The CZM airport is extremely user friendly and small (6 gates). JMHO but I would never go thru Cancun and mess around with that airport and the subsequent trek to Playa to take the ferry. Too much brain damage and wasted time, at least for me.