As the title already say, how does the antenna on the Boeing 737 Max fuselage not disrupt the airflow?
(Boeing) 737 MAX antenna.
Anything new attached to the outside of the airplane will change the airflow in someway; that is unavoidable.
The only question is if it will disrupt the airflow in a way that has a significant negative impact on the plane.
You'll recognize that the antenna is installed very close to the CG, so the new air resistance has virtually no pitching moment.
It is far from any control surface, so those all work the same.
The increased air resistance affects fuel economy a very tiny amount, but paying customers have enough preference for inflight wifi that its worth it.