Howdy y'all. I'm new to the Delta family (despite being a SkyMiles member: I used it just to link it with Lyft back then) after years of exclusively flying WN, AA, and HA, so bear with me:

I booked DL Main Basic on the earliest flight from DFW to SEA. It says the flight will be on an A220. Now, I understand that with main basic I cannot select a seat unless I pay extra to upgrade to Main Cabin. Here are a few questions.

1. Has anybody flown DL DFW-SEA early in the morning? Was the flight full?
2. Any chance of me getting a window when I hit "check-in" at T-24 hours or T-3 at the airport? I know since this is an A220 with a 2-3 seating, I'm sure my chance of getting a middle should be less, at least compared to a 320, 321, or 737. Do they let you pick whatever is available, or do they auto-assign you?
3. How's DFW TSA at 4am? I plan to check-in for my DL flight at around that time frame - and P.S., yes, I do have PreCheck.

The reason I ask question no. 2 is just to familiarize myself just in case the system differs from AA, HA, AS, and WN. I can't say for AA since I usually pay considering their flights out of DFW is very crowded and WN for obvious reasons, but for HA and AS, I've always check in at the airport at T-3 and managed to get windows on their lowest subclass. I understand the risks, so no need for the "if you really want the window seat, pay. Don't ask people to move" comment - despite me loving to take pics outside the window, I'm never a guy who asks people to move just for it. Help me take pictures outside the window only during takeoff and landing, yes, but move, absolutely not.

To answer question 1, just do a dummy booking for the flight you want to take and see what the seat map shows, bearing in mind of course that not all passengers may have selected their seats yet, particularly the BE ones who won�t get that opportunity until T-24.

And a slight variation of the above advice, do a dummy booking for your flight for tomorrow and see how full it is within T-24

IIRC I can view via website by selecting "upgrade to main" when selecting seats...but not pay and just go back from there. I gotta check again though. Idk if paying for a seat at cheaper rate at D-7 still works on DL.

The last time I checked it is possible for a Basic passenger to pick and pay for a seat assignment 7 days prior to departure, without having to upgrade first to main cabin.
Now whether that is cheaper than upgrading to main cabin first and then picking a seat for free, I don't know.
But if upgrading to main cabin first, one could do that now and not have to wait for T-7 days.

Current fare differentials between BE and Main fares on DFW-SEA are $45. I suspect the seat selection fee on a BE fare will be less, but haven't actually checked. You can't pay for a Preferred seat on BE fares according to DL website, but it looks like the A220 does not have a significant number of Preferred seats and there are many non-Preferred aisle/window seats available.

If you cancel a basic ticket using miles do you get the miles credited back?

We'll probably see. My flight is during one of the busy holiday periods so...I kinda expect some variations to happen, but I have set a reminder to do check-in.

That's the reason why I've been holding off buying a seat. Chances of me ending in a window or aisle is higher than middle in an A220, plus the Preferred seats are only a few, so few that it was pretty much negligible as to where I want to sit.

Oh, and another question just out of curiosity, and I apologize for straying a bit: for DFW-SEA's earliest morning flight, will the crews be DFW, SEA, or LGA based?

If you really don't care where you end up sitting, I say go for the gamble. But, if you care, I just want to pass a thought: I fly often and have never seen so many seats disappear the day before a flight. I don't know where these people come from or where or how they have booked, but I have never had an empty seat next to me, or in the plane even, in I can't remember how many years when flying Delta.

If the seats disappear shortly before T-24, it's probably passengers who have connecting flights (into your departure airport) doing OLCI shortly after T-24 for their first segment.

I'd say last-minute business travelers fall into this category.

And this as well - usually if I do connecting flights, my chance of getting a seat I want on the second segment is higher since not everyone has done their check-in procedures. I would expect this if I'm doing DFW-SEA on AA or ATL-SEA on DL, but I think since I'm flying Delta's first flight out of DFW to SEA, chances are this would be unlikely unless if they connect from a fellow South American/European Skyteam partner to Seattle.

I see the same thing with seats being assigned from what would otherwise look like a fairly empty flight, and its because a lot of basic seats are assigned by the system the day before departure. Then other people with basic tickets check in and select seats.

I think the only airline that, at least from the flights I have taken, did this to me was Scoot (TR), but that was because we were in a group booking. They let us block the entire row. Glad to hear that DL has the same pre-assigned-but-can-move method like what JL and NH have. I tbh don't feel too worried as I'm flying on an A220, which has more aisles and windows than middles.

Anyway, I still look forward to my first DL flight in a long while. Surely they can't be worse than AA.

Now it's 30 days, and it seemed like a new policy, but now in the fare condition, they said "seats will be autoassigned and cannot be changed" (like United). It was $44 for me DFW-SEA, but I decided to bite the bullet, pay for it, and seat myself just a row behind the last row of Delta Comfort; there were around 13 window seats left.

Maybe a bit too early since I know the price can drop, but 14E has 1" extra legroom and I'm willing to trade my recline (since I rarely do anyway) and slightly bending forward to see the window for a 1" extra legroom and an empty middle next to me, as of now. That was the only window at the front of the plane; the rest were on rows 19 and back.