Delta has been kicking the tires of Boeing's 737 MAX for years. In 2017, the airline giant conducted a head-to-head competition between the 737 MAX and Airbus' A320neo family.

Delta has 77 Boeing 737-800s that average nearly 21 years old and have 160 seats. Other older, smaller aircraft in Delta’s fleet include Boeing 717s to be retired by the end of 2025, as well as ...