There are Two 797's In The Works

The two in mind would be called the 797R- and 797I-. One,  the "R" version would seat 250 or so passengers and would be a high density step up from single aisle for any regional travel. The "I" version would have a range for going Intercontinental or about 6,000 miles with 220 passengers. Both would be separate designs built on a dual aisle and same engine supplier basis.

Why? Boeing is already building the paper airplanes while lining up "key" suppliers before an announcement, hence the 2020 time extension rather than announcing in 2019. The result is still scheduled for 2025 for the first delivery of one type. Boeing is working on this concept as we speak and will keep secret its true intent. The Asian community will support the high-density "R", or regional type while Europe will eagerly focus on the "I" type or known as the Intercontinental. It stands to reason Boeing is truly wrestling with pulling the wool over Airbus' eyes with these transitional concepts. The Northwest should build the "R" type and Charleston will do the "I" type. Boeing is working on who will do what before committing to the two programs. It needs an engine maker, and it needs dual program management.

This would suggest that "ducks must be in a row and accounted for" before making such a brash announcement. Little lead time is given for an Airbus response since Boeing knows Airbus intel is hard at work playing with Boeing for its own benefit. The A321NEO program cannot address what Boeing will propose with one airplane type so it will go for the "twofer" having a 797R and a 797I, pleasing customers on both sides of the world at the same time. It would be offering, similar to,  making the 737-8 version at the same time as a -10 version is offered but in one announcement. 

Boeing took five years to go through the Max type airplane from a 7-10. This is a start of two programs covering the proverbial gap found from the 737 single-aisle to the 787 dual aisles. The four thousand mile airplane segment which Boeing is addressing would expand to a 6,000-mile unit segment thus encroaching upon both the 787-8 and the 737 Max 10 programs, and both are either filled or are filling rapidly suggesting an overlapping segment for the 737, 797 and 787 programs.

Boeing, at this time, is slow to act on this NMA market because it is more than just filling the gap, it is redesigning its market approach for current and potential customers. If it guesses wrong, Boeing will need decades to recover its scheme in the market place and Airbus will suffer. If it guesses well, then Boeing will hit it out of the park as a home run and Airbus will not recover even with decades of time and money on its hands. Boeing is doing something bigger than an NMA slot filler. It's trying to complete itself with this decision.