Was this recent? I’m not 100% sure on this, but wouldn’t they need to block a good amount of seats with the -800 on SNA-EWR? Doesn’t the 737-800 need a lot more runway to takeoff with a max payload compared to the -700?
The upcoming SNA-EWR flights all seem to be on the -700.
United may have a monopoly on SNA-HNL just because they’re the only airline with an aircraft that can profitably operate with SNA’s short runway. Southwest doesn’t have ETOPS 737-700s, so it can’t operate those from SNA to Hawaii. If they use the ETOPS 737-800s, they’d likely have to block a significant portion of the seats. If Southwest goes for ETOPS on the MAX 7s, that could allow them to enter SNA to Hawaii, but for now they’ve focused on LGB to Hawaii with the new additions of HNL/OGG.
I’m not entirely sure on this though.