DTW is a great base - hardly any weather delays, and a good mix of flying. If only the ER could come back... 320 is where the growth is at DL on the narrow body. 717 is mostly stagnant, 737 is growing slightly but not enough to worry about. As the 757s get parked, the 321 will take over that flying.

1 day trips are hard to do - there aren't that many of them (on 737/320) because they get incorporated into other flying to make it more efficient. Then the senior people pick them up - so unless you're in the top 20%, you won't be able to hold them. 2 days are rarish, and there are plenty of 3-4 days trips. Some 5 days, but the new TA should adjust these to be a bit more equitable.