Originally Posted by
lincolnjkc
I might start taking a tape measure with me -- I wonder if the 7M8/7M9 are slightly higher off the seat track or has slightly less crud hanging off the bottom of the seat because those are the ones I mentioned where I can "barely" get my bag under those with a bit of persuasion -- at least far enough to make the FAs happy (though IIRC without the annoying seat divider thing so possibly an older version of the new seat) -- for the 321 after three flights and trying various orientations (e.g. the 7M8 it has to go under "top" first because the bottom flares just enough to make it not a thing) and "gentle squishing") I've had to just punt to the overhead.
321 in Y (21F, at least) fits very comfortably
The A321 could indeed be worse. I've only been in the A321 F seat once, IIRC, and I think I had to just put it in the overhead bin then. I was in the aisle, so I didn't spend as much effort trying to squish it under the seat in front when there was space above. But it would have been really annoying if I had a window seat.
I've had no problem with fitting it under Y aisle seats either (well, haven't tried on A321), even with some of those being constricted with the seat support in awkward location.