Looks like unless the 4M flight arrives quite early and the AR flight is delayed, the connection just isn't going to happen. I see that all fares except the ejecutiva (full biz) fare have a USD 25 change fee, and I'd bet they wouldn't allow free standby so one has to go landside.

Thinking of taking the AR flight that goes SLA-JUJ-AEP for sightseeing en route but there's the worry that flight is delayed (flown AR some 10 times in the past 18 years and would say at least 30% were delayed, one of 21 hrs).

Yeah, I know AEP is boring but it's better than the one-storey terminal that was used in the early '90s. Maybe take a taxi/bus somewhere and get something to eat. We won't arrive into REL until late.

Alternative is to fly 4M into AEP the night before and then fly to REL either early AM or mid afternoon the next day.