ER does international and domestic. The 765 (767-400) aircraft is larger/holds more pax than all the 7ER category aircraft, so makes sense it does international. Avionics is also far improved, as well as other systems. It's a nicer aircraft, in my opinion. 7ER does have nice trip variety though, great options for doing international and domestic trips. The only domestic the 765 has is JFK-LAX (out of NYC anyway). JFK-HNL is supposed to be a thing this winter. Other than that, you get a select number of international destinations that will vary. Small fleet, so it can only have so many destinations. 7ER is a much larger fleet, so more destinations.