The level of complexity will make this aircraft something like an advanced satellite, where electromagnetic interference, heat offload and power requirements pose compelling and existential challenges to the system.
If you look at Boeing’s sixth generation concept you can see how much physics and low observability (stealth) are driving the form of these aircraft. However, the Northrop aircraft appears to build in more of the all-aspect stealth lessons of the B-2.
Northrop Grumman has released new design concepts for sixth-generation fighters for the U.S. Air Force and the U.S. Navy. The Pentagon hopes to field next-generation fighters to replace those aging platforms by the mid-2030s, but there are questions as to whether there is enough money in the budget to develop two completely new warplanes.
The Pentagon could enter into a Milestone A technology development phase somewhere between 2018 and 2019. Following an optimistic timeline, the Navy F/A-XX and Air Force Next Gen Air Dominance (NGAD also know as F-X)—program could reach a Milestone B source selection decision in 2025. Then, the engineering and manufacturing development phase would take about ten years. That would allow for a 2035 entry into service date for the new aircraft. But, industry sources cautioned, that’s a 'best-case scenario.'
The Pentagon has learnt from the $400 billion F-35 Joint Strike Fighter debacle—the F/A-XX and the NGAD are likely to be separate programs that share common technologies
Both aircraft designs are likely to use adaptive cycle engine technology—which optimize the power plant’s bypass ratio for its given airspeed and altitude
SOURCES - Northrop, Breaking Defense, National Interest