Delta Air Lines operates one of the most diverse fleets across the global airline scene. With 10 different aircraft types and 17 individual variants across their mainline fleet of 989 planes, there is something to like for just about any aviation enthusiast or plane spotter alike. But, for the purpose of this article, we will focus on one of their more treasured and adored fleets by many, the Boeing 757. 

With over 100 aircraft of the type still on the active roster, Delta is able to accomplish many tasks with the versatile jet (while also being the largest operator of it). The versatility of the 757, however, also comes as a problem to Delta. The last Boeing 757 (which Delta owns) was produced in April 2005, making the jet just shy of 20 years old, and many more of them are north of the 25 to 27 year old range. This brings up the age-old topic of what Delta will replace its 757s with, and when.

Capacity

Delta currently operates both the 757-200 and 757-300, with roughly 8 of the baseline jets and 16 of the stretched variant. Capacity-wise, the 757-200 currently has a maximum seating arrangement of 199 passengers in its highest density domestic configuration, with a smaller sub-fleet of jets maxing out at 193 passengers, mainly due to the different exit door configuration than the 199-seat planes. 

There is also a sub-fleet of 757-200's that has Delta One seats installed, and thus an ever lower capacity at 168 passengers. However, these jets are being converted to the 193-seat layout starting late 2024. The 757-300s operate with a 234-seat configuration, and this is where we address the first issue with replacing the 757: capacity. 

The 757-200 is a non-factor in this topic, as both the A321ceo and A321neo are essentially 1-to-1 replacements, seating 191 and 194 passengers respectively. The 757-300 is the real problem here, as these aircraft are used for extremely high density routes that would otherwise need either additional daily flights or a widebody (which would be uneconomical on shorter domestic flights that the 757-300 does). 

There is simply no available narrowbody aircraft on the market that can seat what a 757-300 does in a multi-class configuration. It can be done in an all-economy layout, but Delta is a premium airline that offers premium seating, thus requiring more space in the aircraft.

Range

The 757 was built not just to be a high capacity hauler, but a long distance flier for an aircraft of its size. Across Delta's sub-fleets of 757s, the domestic aircraft can fly up to 3,900 miles, while the lower capacity aircraft with Delta One are capable of stretching their legs as far as 4,700 miles. 

Historically, I've seen Delta 757 fly routes such as Atlanta-Anchorage (3,417 mi), New York-Dakar (3,830 mi), and Raleigh-Paris (4,052 mi). All of these routes are outside the range of the A321, and would require an A321LR or even A321XLR to attempt to make it happen. However, these Airbus competitors would likely take a payload hit to allow them to even make it happen, which is where we cover the final topic of this debate, performance.

Performance

The 757 is nicknamed by many as the "Ferrari of the skies" for good reason. The 757 is equipped with either RB211s, capable of up to 43,500lbs of thrust, or the PW2037s, capable of up to 42,000lbs of thrust (Delta has the latter equipped on their 757s). 

These engines, for the size of the 757, make the aircraft well overpowered, and allow the plane to do things other aircraft just can't. With a full payload, I've seen 757s rocket out of Santa Ana on a transcontinental flight to Atlanta. The significance of this is that SNA has an extremely short runway, only 5,700ft in length. An A321 or A321neo would need to take less passengers and/or cargo in order to have the sufficient performance to take off from this airport on the same mission. 

High altitude airports pose the same scenario, with 757s being able to use their excess power to perform fully-loaded takeoffs from airports like Eagle/Vail, which sit at an elevation of 6,547 feet. An A321 would yet again need to take a payload hit, as their engines are less powerful and more optimized for the size of the plane, compared to the oversized and more powerful engines installed on the 757.

The Bottom Line 

The 757 is undoubtedly an amazing and well-built aircraft. It has evolved from being a 727 replacement to being so much more, and Delta has absolutely taken advantage of these statistics in their day-to-day operations of the jet. 

But like all good things, the days of the 757 must come to an end at some point in the future. However, replacing the jet will be a struggle. The A321 is a decent replacement in some characteristics, but still lacks in all 3 core aspects discussed in this article. It does not offer capacity to replace the 757-300s, it does not have the range to match the 757-200, and even if it does get close, it will take a performance hit that will reduce the allowable maximum load of passengers and cargo, resulting in lost revenue that could've otherwise been captured if a 757 was used instead. 

It is likely Delta will keep flying these jets as long as they possibly can in an economical matter, and hopefully by then a more suitable replacement will come into the light. But for now, we must enjoy these incredible aircraft while they are still around in a plentiful number, and appreciate the things they have done not just for Delta, but the aviation industry as a whole.