I routinely fly IAD-LAX and back on the 777s, normally Mon and Thurs and these always fill up. Heck I did 2 BWI-LAS MRs these past 2 weekends and 6 of the 8 flights were completely booked (side note, both weeks the seat maps for the DEN-LAS segment showed less than 10 folks in E+ the morning of flight, only to be completely filled during boarding. Could've been irreg ops from earlier flights I suppose). Then this morning, on my ORD-BWI leg, w/12 open seats, I noticed a 735 going to MSP with 70+ seats opened.