The phrase "fly off course" is correct and usable in written English.
It is usually used to describe a situation in which someone or something is heading in the wrong direction or is not following the expected path. For example: "The plane flew off course in the storm and ended up landing in a different city than the one planned."
NASA issued a report that a weather plane had flown off course and possibly crashed in Soviet territory.
Miller won two silver medals in the 2002 Salt Lake Games and could have had a third except that he extended himself trying for the gold medal and flew off course.
But the AC-130 launched early, flew off course, dodging what the inquiry determined was a surface-to-air missile, and experienced a series of on-board communications and sensor system failures largely cutting it off from the ground during the pre-dawn mission.
The US imposed a blockade on Cuba, and Soviet ships threatened to break it - the US also considered invading Cuba, and Castro readied the island for war. 5. On October 27, the crisis reached its climax after one US spy plane was shot down over Cuba, another was fired upon, and a third aircraft flew off course over the USSR.
Their suspicion has hardened that it was flown off-course by the pilot or co-pilot, or someone else with detailed knowledge of how to fly and navigate a large commercial aircraft.
However, a later report by Malaysia's Ministry of Transport, which was released on the anniversary of the plane's disappearance, suggested that the plane was flown off course deliberately - due to the transponder being switched off by someone in the plane, rendering it invisible to civilian radar.
She went to see a twelfth-century minaret that had been discovered by archeologists only in the previous decade — she heard that it had been spotted from the air by a pilot flying off course — in a semi-deserted region of the country.
Officials believe the plane flew off course for an unknown reason and went down off the west coast of Australia.
Dominique Maltais of Canada collided with a competitor and flew off the course and into the safety netting.
While speeding through a series of bumps about midway down, Rahlves, 36, lost his balance while trying to make a pass and flew off the course.
