Officials from several of the top airlines in the United States have said the possibility of mandating COVID-19 tests before domestic flights would cause major issues.

According to USA Today , officials from American, JetBlue, Southwest and other carriers have said they do not support requiring coronavirus tests before domestic flights, but they have no additional information on the possibility actually coming to fruition.

The concerns arose after the Centers for Disease Control and Prevention (CDC) official Dr. Marty Cetron announced Tuesday the organization was working with the U.S. President Joe Biden and his administration regarding the types of tests that would be required and where they would be administered.

While most airlines have fully embraced the CDC’s orders to require a negative COVID-19 for all international travelers arriving in the U.S. despite the extra costs and manpower needed, the domestic testing opens up several potential issues.

JetBlue President Joanna Geraghty told USA Today said there already problems with acquiring enough coronavirus tests and adding the need for more for domestic flights would result in bookings taking an even larger hit .

Southwest Airlines CEO Gary Kelly said he believes the domestic testing policy would be a “mistake” and “wholly impractical.” Other officials remain confused about why airlines would be forced to require COVID-19 tests, while other forms of transportation would not have to meet the same standards.

“People need to travel. They'll figure out a way to get there,” Geraghty continued. “They'll figure out a way to see Mom, Dad. And, frankly, putting this burden on air travel is, we think, far too cumbersome.”

In addition to the logistical nightmare of acquiring and administering coronavirus test to every airline passenger flying in or to the U.S., there are questions of workload being increased on employees who are already at capacity completing COVID-19 health and safety protocols.

U.S. Travel Association CEO Roger Dow said the group is opposed to COVID-19 testing for passengers on domestic flights , but in favor of it for international routes. He said the association is also opposed to quarantines because they are “disruptive” and difficult to enforce.

Earlier this week, several airlines in the U.S. reported fourth quarter and year-end results, with massive losses due to the impact of the ongoing coronavirus outbreak being felt across the industry.