FedEx has warned of a global recession, cutting its sales forecast by half a billion dollars

The company’s shares fell 21% in premarket trading on Friday after it warned late Thursday that a slowing economy would cause it to fall $500 million short of its revenue target. The weakening global economy, particularly in Asia and Europe, has hurt FedEx’s express delivery business. The company said that package demand weakened in the final weeks of the quarter.

The company said it is responding by reducing flights and temporarily parking aircraft, reducing hours for its employees, delaying some hiring plans and closing 90 FedEx Office locations and five corporate offices.

FedEx (FDX) said adjusted earnings for the quarter ended Aug. 31 will fall $260 million, or 17%, from a year earlier. Revenue rose $1.2 billion, or 5%, despite missing the company’s first target.

FedEx Ground service, which is the company’s primary way for US consumers to handle shipments of online purchases, missed its sales target by $300 million.

The company uses independent contractors, not employees, to make deliveries, and many of those contractors complain that rising costs of fuel, labor and new vehicles have made their business unprofitable. Some are threatening to suspend operations on Black Friday, the start of the holiday shopping season, unless FedEx agrees to change their compensation.

FedEx insists it will work with troubled contractors. He has sued the former contractor who has been the company’s most vocal critic.

“We recognize that the current economic climate is creating new challenges,” FedEx Ground said last month. “We remain committed to working one-on-one with service provider companies to address the challenges specific to their situation. Our goal is to enable success for both FedEx Ground and service providers.”

About 1,000 of the 6,000 contractors who work for FedEx have joined a trade association to get better compensation for the company.

According to an association survey released this week, 54 percent said their business with FedEx was losing money, 35 percent were making a profit and only 11 percent were profitable. According to the association, the survey reached 1,200 contractors working in the company or those who left the company in the last 12 months.