Even more ironic that 1K is compression of "Premiere Executive 100K" Kinda suggests that 1K is a species of 1P.
And indeed it was and is an offshoot of Premier Executive. It was a totally unofficial and internal sub-set designation when it first started. So much so that many 1K's didn't even know they had a special designation at first!
A post of mine on this from over 6 years ago in November of 2000:
Not a dumb question for a outsider (and many "insiders") to ask.
Millions of years ago, when dinosaurs ruled the earth...Premier Executive was United's highest status level. Then, within Premier Executive they started to sort of secretly reward their 100,000 mile fliers (this is why technically, it's still known as "Premier Executive 1K").
The 2 digit data entry and display field in United's ancient computer systems for 100,000 mile flier was designated as "1K" (Premier is 2P, Premier Executive is 1P, even to this day).
United employees just started calling these customers "1Ks" after that status code, and it just kinda stuck. Now it's a well known "brand" and while many at United would agree that they wished it were 100K from the start, they pretty much agree that it's an established and well known brand now that they'll keep for awhile.
FYI, on
manifests,
tickets, check-in screens and such, it
is indicated as "100K"
Above from:
http://www.flyertalk.com/forum/showthread.php?t=90499
