As other posters have noted, there are routes that often get lie flat but this is not something you can always count on -- there is no lie-flat domestic guaranteed lie-flat service beyond the noted transcons with D1 though we've seen lots of wide body planes that would typically be serving international routes show up domestically. Last summer, MSP and ATL to PDX were regularly 767 and A330. This year, not so much. This week, on one single day, DL is flying a 767-400 from JFK to PDX but.. that's not a route that regularly receives a wide body so would not be a "route" I'd list for a lie-flat. And with so many things changing in the industry, there is no guarantee that lie-flat seat you see on the schedule in June will still be lie-flat when we get there...