Thanks for the definition.
How on earth, then, was an 16 year AAA pilot quite junior while a 16 year AWA pilot quite senior pre-merger?
Here's another definition:
lon·gev·i·ty
[lon-jev-i-tee, lawn-] Show IPA
–noun
1.a long individual life; great duration of individual life: Our family is known for its longevity.
2.the length or duration of life: research in human longevity.
3.length of service, tenure, etc.; seniority: promotions based on longevity.