### Question
How is the term 121 mainline passenger carrier defined?


### Answer
The term **121 mainline passenger carrier** is defined in *39 U.S.C. § 5402* as the following:

> a mainline carrier providing passenger service through scheduled service on routes under part 121

#### Citation:
  - *39 U.S.C. § 5402*
  - Heading: **PART V-TRANSPORTATION OF MAIL > CHAPTER 54-TRANSPORTATION OF MAIL BY AIR**

