New York-based Atlas Air Worldwide Holdings announced Aug. 24 an agreement to supply air cargo carrier FedEx Express with five Boeing 747-400 freighter aircraft during the December peak-flying seasons of 2017 through 2021.

The new agreement is in addition to an already existing arrangement between the two companies for five freighters to be utilized in the upcoming 2016 peak flying season.

Peak flying season is generally described as the month of December, though sometimes the period begins earlier, Atlas Air said.

"[While] we have worked closely ... with FedEx for many years ... this is our first agreement that allows both companies to plan for the longer term," Atlas Air President and CEO William Flynn said. Terms of the agreement were not disclosed.