I’ve noticed that Delta’s flights from JFK to the Caribbean seem to take a more circuitous route, staying much closer to land, than other airlines operating the same routes. Delta tends to head southwest along the East Coast to North Carolina, then turn southeast towards the islands. The other airlines (as has been my own experience flying to the Caribbean) generally head straight out to sea, on a more direct path. For example, compare the following, all on the same day:
JFK-SJU on Delta (738): http://flightaware.com/live/flight/D...5/history/20100217/1351Z/KJFK/TJSJ
JFK-SJU on JetBlue (A320): http://flightaware.com/live/flight/J...9/history/20100217/2048Z/KJFK/TJSJ
JFK-STT on Delta (757): http://flightaware.com/live/flight/D...3/history/20100217/1329Z/KJFK/TIST
JFK-STT on American (757): http://flightaware.com/live/flight/A...5/history/20100217/1216Z/KJFK/TIST
JFK-ANU on Delta (738): http://flightaware.com/live/flight/D...7/history/20100217/1348Z/KJFK/TAPA
EWR-ANU on Continental (738): http://flightaware.com/live/flight/C...8/history/20100217/1432Z/KEWR/TAPA
Delta seems to follow similar routes with both 757s and 737-800s, both of which should be capable of taking more direct routes from an ETOPS perspective. The fact that three other airlines took the more direct route on the same day (and that this seems to be the case almost every day) suggests that weather wasn’t an issue. Is there some cost savings associated with non-ETOPS routes that offsets the additional fuel costs from the increased flying time?