Based on all the flying jobs i have had.....this can be a very difficult one to answer. Flight instructing, colgan air, and allegiant air......each job i was hired along with other people hired on that same day/same class. I would say it is probably fact that no two people in my class have the same #'s on the W2 at the end of the year. I can only speak for the places i have worked. There are just so many factors.
Whether you live in base or not.
Senority.
Commuter or non-commuter.
Schedule preference.
Whether the company is adjusting pay or not. (this happens at all airlines)
either pay raise or pay cut. (pay freezes too)
Whether you take upgrade or not.
Whether you can get called for upgrade, or get the possible recommendation letters for upgrade.
Whether you can pass your upgrade or not.
Whether the company is short or fat on pilots.
QOL preferences.
I honestly think i would have a hard time estimating my W2 for next january right now within $10,000. Airline pilot pay online tells part of the story.
It's probably easier at stagnant airlines, (no growth, no shrinkage) to guess what you will make for the year. I wouldn't call airtran a stagnant airline.