Almost 30 years in this industry and I think this is as simple as I can make things based on my observations.

You want your company to be the gray man. Make a little money but don't do too well. You don't want it to be terrible and flirt with bankruptcy either.

If the company is too well run and accrues a bunch of cash and equity (FDX, WN), the sharks on Wall Street will circle and come for the money at the expense of the company and the employees.

If the company teeters on bankruptcy (US Air/TWA/Spirit) it is also a target. Whether for a cheap acquisition/merger or for the bigger airlines to kill and eliminate a competitor it doesn't usually end well. This scenario also introduces courts and regulator - neither of which will be helpful to the employees.

If your company puts its head above the ridgeline in either fashion, that's when its time to worry.