- Boeing's upcoming 737 MAX 10 was recently given the green light to start certification test flights.
- The high-density plane will compete with the Airbus A321neo but has faced development problems.
- Insider toured the 737 MAX 10 testbed at the Paris Airshow to catch up on the certification process.
Boeing's upcoming 737 MAX 10 is the largest of the single-aisle jet family and will compete with Airbus' A321neo.