HUH: Amazon is struggling to hold on to the pilots who ship your packages.

Amazon’s promise of one-day shipping has led it to increasingly rely on its own air cargo division, Amazon Air. But as the number of shipments pushed through the cargo arm multiplies, the pilots who fly those packages continue to voice that they are overworked and underpaid.

The pilots don’t work for Amazon directly, but are employed by the contractors Air Transport Services Group (ATSG) and Atlas Air. More than 200 cargo pilots who fly for ABX Air, which is a division of ATSG, cast a vote of “no confidence” against management’s ability to resolve ongoing labor disputes, reported Reuters earlier this week. In total, all but one member of the pilot’s union voted “Yes” on a resolution that asked if they had “no confidence in management’s willingness to negotiate or reach an agreement for the benefit of all stakeholders to include the shareholders, the customers, and the employees.”

The pilot union, the Airline Professionals Association, has battled with the management of ATSG for five years to negotiate new work rules for its pilots. Issues involving how pilots are scheduled for their routes, salaries, and retirement still remain unresolved.

Those who fly for Atlas Air, another cargo operator used by Amazon, recently lost a three-year bid to secure a new work contract. Atlas pilots protested outside an airport in Cincinnati, Ohio for better workplace conditions in April. And in February, Atlas pilot crashed an Amazon Air flight, killing all three of its occupants, which some have suggested was linked to its staff being overworked.

Pilots at both airlines have complained about low morale, low pay, and poor workplace retention. Such troubles are brewing during a global pilot shortage, and many well-trained pilots who work for Atlas and ABX have simply left for better opportunities. A union survey earlier this year found that 60% of the pilots who work for the three airlines employed by Amazon (ABX Air, Atlas Air, and another called Southern Air) are looking for work elsewhere.

“We still have very experienced high quality pilots leaving for other carriers because they have better pay and better schedules,” Rick Ziebarth, an ABX Air pilot and executive council chairman of Airline Professionals Association Teamsters Local 1224, told Quartz. Ziebarth argued that as a result of well-trained pilots leaving, ABX is forced to hire people with far less experience who require more training. Quartz has reached out to Amazon for comment on the matter.

qz.com/1763226/amazon-air-is-struggling-to-hold-on-to-into-pilots/