The Frontier Airlines flight, operated by Chautauqua Airlines, was scheduled to leave Omaha at 6 a.m., but did not leave Eppley Airfield until just before 8 a.m., KETV-TV, Omaha, reported.
Frontier Airlines has a zero-tolerance policy on drug and alcohol use by employees and had another pilot brought in to fly the plane, the airline said in a statement.
The flight, which carried 29 passengers and three crew members, arrived safely in Milwaukee at 9:29 a.m.
Frontier and Chautauqua airlines, along with the Federal Aviation Administration, are investigating the incident, KETV said.
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