After multiple emergency calls around 3:15 pm local time, emergency services reached the scene near the village of Zemmer, police said in a statement.
The airman was taken to hospital. Police said it was not immediately clear how seriously he was injured in the crash.
Authorities blocked off a large zone around the crash site including several roads, the police statement added, urging drivers to avoid the area.
A spokesman for the nearby US military airbase at Spangdahlem told AFP he had no further information about the crash, its causes or the health of the pilot.
Germany is no stranger to military aircraft crashes, including in its own shortage-plagued Bundeswehr armed forces.
One of the pilots was killed, while the other ejected to safety.
Less than a week later, a helicopter pilot died when his aircraft crashed near an army training centre.
The last American military crash in Germany dates back to 2015, when one of the Spangdahlem base's F-16 fighters went down in northern Bavaria.
In that incident, the pilot survived after ejecting from the plane.