Cargo pilots are pushing for more rest between flights.
The Federal Aviation Administration recently changed flight and duty rules to increase the amount of rest pilots get between flights, but the rule only applied to pilots of passenger planes.
Sen. Barbara Boxer, a California Democrat, on Wednesday introduced the Safe Skies Act to extend the rule to include cargo pilots.
"Current science says that you cannot segregate between the two," said Capt. Lee Collins of the Independent Pilot Association. "All pilots are human beings, all pilots get tired equally at the same rate and by the same measure.
"It makes no difference whether you're flying people or you're flying cargo."
The Independent Pilot Association is a union that represents pilots of the United Parcel Service, UPS.
Mike Mangeot, a UPS spokesperson, said pilots employed by the shipping company already fly different route structures to include fewer flights and more rest between flights.
"UPS goes to great lengths to make sure crews are rested and and fit for duty," Mangeot told KTUU.
Collins said it is good to see politicians on both sides of the aisle working together on the bill.
"We are by no means ready to say or declare victory," Collins said. "We just know that today was one more important building block in this effort."