American Airlines (NASDAQ: AAL) has agreed to provide $4.2 billion in extra pay and benefits for its flight attendants over five years under a tentative collective bargaining agreement announced last week, the union representing the staff members said Friday.

Association of Professional Flight Attendants, which led contract negotiations with the carrier, announced details of the agreement following a meeting with the board and executive committee on July 24.

After the contract is approved, the employees will receive Immediate salary boost of 18%-20.5%, followed by salary increases of 2.75%, 3.0%, 3.0% and 3.5% in subsequent years. Total salary boost of 33%-36% over the contract period.

A tentative agreement reached last week has averted a major union action by American Airlines’ (AAL) 28,000 cabin crew.

“This agreement is not just our victory today, but the foundation for a fairer future for all flight attendants,” the union said. The tentative deal must be ratified by frontline workers in a vote starting next month.