Boeing and Airbus are the two largest plane manufactures in the world. The 737-900 and A321 are the most common planes that they manufacture, respectively. Anyone who travels with regularity, will have spent time in both the 737-900 and A321. Both the A321 and 737-900 are workhorses for Delta, everything from trunk line routes between hubs to trans-continental flights and even short routes like GSP-ATL, Delta uses the A321 and 737-900.
Delta has about 130 of both the A321 and 737-900. Both Delta planes have 20 First Class Seats, ~140 Main Cabin(economy) seats, but the A321 has 29 Comfort Plus seats where the 737-900 only has 21. So while they are close to the same size, the A321 does have a few more passengers. From a performance standpoint, both the A321 and 737-900 are pretty similar. They both can run similar routes within the Delta system.
What plane is more comfortable for passengers? The Delta A321 vs 737-900? As the title implies, the Delta A321 is pretty much always more comfortable than the Delta 737-900. In all cabins, I’d rather ride on the A321 vs the 737-900. Anyway let’s get into why.
Date of Review: September 2022
In This Guide
Delta 737-900 vs A321: First Class Comparison
Delta A321 and 737-900 First Class Snack and Meal Service
Delta uses the 737-900 and A321 on similar routes, the service that will be provided on these flights will be broadly the same. On short routes drinks and snacks will be provided. On longer flights a meal will be served. There’s no difference in the quality or quantity of the meal service between the Delta A321 and 737-900.

Here’s a drink and snack provided on a short Delta A321 flight. In first class on both planes, beer, wine, and mixed drinks are included.

Here’s a breakfast that was served to me on a slightly longer flight. As I said, the meals will be the same on the A321 and 737-900.
Delta 737-900 First Class Seat Comfort

On the Delta 737-900 in first class, there’s a comfortable amount of leg room, but I just don’t find the seats that comfortable.

The good news is that there is great in-seat entertainment on the 737-900. The screens in first class are large and very responsive. The selection is also very good.
Delta A321 First Class Seat Comfort

The Delta A321 first class seats have about the same amount of leg room as the 737, but they seem a little bit more comfortable. They have just a little more space and width.

The in-seat entertainment in First Class on the A321 is also very good. I think it’s the exact same system as on the 737-900. Lots of selection and very responsive.
Delta A321 and 737-900 First Class Amenities
The amenities provided on the Delta A321 and 737-900 are also pretty much the same.

Both planes provide power in every seat, both USB and 110v via a universal power port.

One thing I don’t enjoy about the Delta 737-900 is the overhead panel. The air vents are terrible. They just don’t put out enough air. This is an issue across the whole plane and isn’t specific to the First Class cabin.
Delta 737-900 vs A321 First Class Comfort Bottom Line
I’m not sure what it is, but the A321 is just more comfortable than the 737-900. The cabin is just a little bit wider, the seats are a little more spaced out, the overhead bins are a little farther away, and the seats are just a little more plush.
Delta 737-900 vs A321: Comfort Plus Comparison
Delta Comfort Plus is their extended leg room economy offering. The seats are exactly the same as in economy, but they have a little extra leg room. They also do get some upgraded snacks and drinks.
Delta A321 and 737-900 Comfort Plus Snack Service
Just like in First Class, the Snack service on the A321 and 737-900 in Comfort Plus will be pretty much the same. On really short flights, there might not be any service. On longer flights there is a drink and snack service. The drink selection includes complimentary beer, wine, and liquor. Then there’s also a separate snack basket for Delta Comfort Plus.

Here’s a drink and snack that I had on a recent Delta 737-900 Comfort Plus flight. No meals are provided in Comfort Plus on either the Delta 737-900 or A321. But then again, neither of these planes fly super long flights. If you want a meal, bring one from home.
Delta 737-900 Comfort Plus Seat Comfort

The Comfort Plus Seats on the Delta 737-900 are in a 3-3 configuration. They are right after the First Class section before the regular economy seating.

The leg room in Comfort Plus on the 737-900 is good. Not as good as first class but not as tight as the Main Cabin.

The in seat entertainment is very good on the Delta 737-900. I again think it’s pretty much the same as the A321.
Delta A321 Comfort Plus Seat Comfort
Here’s where things get a little different. Because of the exit row configuration on the Delta A321, there are some amazing Comfort Plus seats and some that kinda suck. Row 13 on the A321 is where this is most evident. Seats 13ABC suck if you’re a window person. It’s misaligned and not a good view.

Seats 13EF are fantastic. Lots of legroom and a great view. There’s also only 2 seats on this side of the plane. How great is that, pretty much unlimited leg room.

While it would appear there’s no In Seat Entertainment, they are contained in the arm rests. You cannot use them during takeoff and landing, but during the flight it’s not bad at all.

The pretty much unlimited leg room and the single seat mate make this my favorite Comfort Plus seat on the Delta narrow body fleet. The other seats in Comfort Plus are much less impressive making the A321 a little more hit and miss where the 737-900 is very consistent in Comfort Plus.
Delta A321 and 737-900 Comfort Plus Amenities
In Comfort Plus on both the Delta A321 and 737-900 there is very little difference. Both planes have power, both planes have good In Seat Entertainment, and both seats are reasonably comfortable.

Again the overhead vents on the 737-900 are bad, like seriously useless. I just hate these things and wish they would go away. The ones on the A321 are much better.
Delta 737-900 vs A321 Comfort Plus Bottom Line
In Delta Comfort Plus both the A321 and 737-900 are good. Much better than in economy but there are a few distinctions. On the 737-900 I would say the seat comfort and experience is more consistent, all of the seats are pretty much the exact same.
On the A321, Delta Comfort Plus has a lot of variability. Row 13 alone proves this, but it’s also a great seat on the right side of the plane in the EF seats. The other Comfort Plus seats are pretty standard.
At the end of the day, I’m glad to ride in Comfort Plus on both the Delta 737-900 and A321, but I’d rather the A321 if I can get seat 13F.
Delta 737-900 vs A321: Main Cabin Economy Comparison
Ok, comparing Main Cabin Economy seats on the A321 and 737-900 is boring. But then again, that’s the point of Kinda Boring.
Delta A321 and 737-900 Main Cabin Economy Snack Service

On both the A321 and 737-900 Delta serves the exact same snack and drink service. On this A321 flight I had a water and some almonds. The cookie I brought from the lounge. There’s no reason to pick either plane for the drink and snack service. Soft drinks and a snack are included on both.
Delta 737-900 Main Cabin Economy Seat Comfort

The Delta 737-900 in economy is a very standard experience. There are some decent exit row options on the plane. This can get you some extra leg room.

The 737-900 has good entertainment options, but I just don’t find the seats that comfortable.
Delta A321 Main Cabin Economy Seat Comfort

The A321 Main Cabin Economy seats are fine, not amazing but they work. I do think they are a little bit better than the 737-900, just seem to have a little more space.

The Main Cabin Exit rows on the Delta A321 have a ton of leg room, but like in Comfort Plus, there are some visibility issues in the window seats.

Not the best view. But at least the leg room is good.

The in flight entertainment in Main Cabin Economy is very good, just like on the 737-900 there is a good selection and the screens are very responsive. Delta does a really good job with entertainment on both the 737-900 and A321 in all of the cabins.
Delta A321 and 737-900 Main Cabin Economy Amenities
The Main Cabin Economy Cabins on the Delta 737-900 and A321 are pretty much the same. Both planes have WiFi for a fee, good entertainment options, and in seat power. It’s an economy seat, there’s not too much to say about features.

These overhead vents on the A321 are just so much better than the 737-900. I’m not one to run hot, but on the 737-900 I really just hate the lack of air flow.
Delta 737-900 vs A321 Main Cabin Economy Bottom Line
Here is where the Delta A321 really outshines the 737-900. In economy, I’d take the A321 by a mile. Unlike in First or Comfort Plus where the two planes are pretty similar, if I have the option, I’ll steer myself towards the A321 instead of the 737-900.
It’s not often you get to choose, price or schedule is often the deciding factor and comfort and plane selection is not the priority, but sometimes it’s a possibility. In those situations I’ll be on the Delta A321.
Other Reviews
If you’d like to check out a full review of these planes:
Delta A321 First Class vs Comfort Plus vs Economy Flight Review
Delta 737-900 Economy Flight Review