IIRC, all flights out of EGE (except maybe to DFW) are weight restricted, and they don't sell all 188 seats on them. For anyone who's never flown out of EGE, it's quite an experience - you need to get off the ground quickly. All the way to EWR, it wouldn't surprise me if they held back 40 or more seats, which is why it looks like there are so many empty ones in the seat map (which is never a reliable, oh never mind...)