Last night I was killing time on FlightAware and noticed DL3325 DTW-MDT circled very briefly in a holding pattern just short of MDT, then returned all the way to DTW. Interestingly, an AA flight landed maybe 20 minutes later. There was fog in the area, but why would it circle for such a short time then return back to DTW (past PIT, CAK, CLE etc)? Logistically I understand it’s easier to reaccommodate from DTW (thought it arrived at midnight) but it only circled maybe twice then returned. And do they really have that much fuel on board?