The pilots at American Airlines have until 12 p.m. to cast their votes either in favor or against the latest contract offer from the bankrupt carrier.
The tentative agreement includes pay raises and a 13.5 percent equity stake in the restructured airline in exchange for more domestic code-sharing and more regional jets in American's fleet.
The Allied Pilots Association expects to announce the results of the votes shortly after noon on Friday at its headquarters in Fort Worth.
"I hope every member in good standing takes the opportunity to cast a vote in this critically important contract ratification," APA president Keith Wilson told pilots in a membership note on Thursday. "The stakes are too high for anyone to remain on the sidelines."
The pilots rejected a previous contract offer in August with 61 percent of the pilots voting against it.