Within that link:
1. Southwest has made significant progress with ETOPS, the twin engine, over water certification required for Hawaii flights. We understand that Southwest recently obtained ETOPS certification for flights over the Gulf of Mexico. Before that approval, we were told by our Southwest pilot friends that flights had to hug the coastline.
I'm not sure how 'recent' that ETOPS is, being that they've been flying to the Caribbean for over 2 years now.