This seems like a non-trivial issue if Delta expands this domestic-widebodies-are-D1 trend. It never impacted the traditional Domestic D1 routes much before because so many of those metros already had wide connectivity to all but the smallest origination airports.

I guess part of the thinking on these mix-market segments they can funnel premium connecting traffic into the narrowbody F seats which will constrain F inventory for the higher yielding nonstops incenting D1 demand. But still, seems questionable in terms of constraining connection opportunities and frustrating customers on why they can't book into a certain flight.

Wonder if they will ever allow Domestic F - Domestic PS married segments if they won't allow Domestic F - Domestic D1 pairs.