American Airlines is suspending pilot hiring as the rapid spread of coronavirus hurts the travel industry, according to a note from the company, the latest measure by a major carrier to stem the pain from a sharp drop in travel demand.

Airlines around the world are reeling from travel restrictions and a plunge in demand for air travel, aviation's biggest crisis since the Sept. 11 terrorist attacks. Even U.S. carriers who boast stronger balance sheets than in previous crises are taking drastic steps, including deep flight cuts and unpaid, voluntary leave, to cut costs.

Airline executives warned at the JP Morgan Industrials Conference, which was held online because of coronavirus, warned booking trends could worsen before they improve.

"As you are aware, COVID-19 has had a significant impact on our flight loads," said a note to American's pilots, which was viewed by CNBC. "The impact is substantial, and unfortunately, the decision has been made to temporarily suspend new hire pilot hiring beyond our March 17, 2020 class."

American did not immediately respond to a request for comment.

The airline isn't the only carrier to push back hiring. United and JetBlue last week announced hiring freezes and offered employees unpaid, voluntary leave.