US President Donald Trump refrained from launching additional strikes against Iran in part because Pentagon officials warned that Iranian forces were adapting to the air campaign, The New York Times reported on May 19, 2026, citing officials.

According to the publication, Iranian commanders studied the flight patterns of American fighters and bombers, making US actions more predictable and increasing the effectiveness of Iranian air defenses. Officials cited the downing of an F-15E Strike Eagle and the damaged F-35 Lightning II as signs that the threat to American aviation was growing.

This Pentagon admission comes amid a protracted conflict that has already cost the US tens of billions of dollars and become extremely unpopular domestically. As the NYT notes, Trump has repeatedly threatened new military action against Iran, but has always backed down, hesitating to resume hostilities.

It was previously reported that the United States had lost at least one F-15E since the conflict began on February 28, 2026. Iran also claimed to have damaged an American F-35 fighter jet. However, the Pentagon has not officially confirmed these losses, and independent sources have only confirmed that the F-35's fuel tank was damaged during in-flight refueling.