The executives secretly set up what were called "Secular Trusts" to pay themselves millions right out of the Delta treasury just prior to declaring bankruptcy.
The trusts were all fully funded and untouchable by the creditors.
Management said it was a "retention program" to keep top talent from leaving a bankrupt company. That's where "SERP" acronym comes from. "Supplemental Executive Retention Program".
Except, as soon as their trusts were funded, they all left.