The pilot was conducting preflight checks at about 6:30 a.m. when airport police officers acting on a tip boarded the aircraft, Minneapolis-St. Paul International Airport spokesman Patrick Hogan said. Officers made him take a Breathalyzer test and arrested him on suspicion of being under the influence of alcohol.
"There was a witness who smelled what they thought was alcohol on the pilot's breath and notified police," Hogan said. Passengers had not yet boarded the flight to New York's LaGuardia Airport, he said.
The pilot has been suspended pending an investigation, said Matt Miller, a spokesman for American Airlines, which uses Eagle to operate shorter connecting flights. Both airlines are owned by AMR Corp.
The company is cooperating with authorities and will conduct an internal investigation, Miller said.
The flight was delayed about 2 1/2 hours while a replacement pilot was arranged, he said.
After the pilot was taken to Fairview Southdale Hospital to have a blood sample taken for testing, he was returned to the custody of airport police, Hogan said.
The alcohol limit for flying is generally lower than for driving a car. Federal rules prohibit pilots from flying within eight hours of drinking alcohol or having a blood-alcohol level of 0.04 percent or higher, half the level allowed for motorists in many states.
Pilots face drug and alcohol testing when they seek a job, are involved in an accident or return from alcohol rehabilitation. Some are selected for random tests. More than 10,000 pilots are tested each year and about a dozen flunk the alcohol part - a number that has remained mostly steady for more than a decade, according to federal statistics.
Twelve pilots failed the breath test in 2011, 10 in 2010, and 11 in 2009, according to the Federal Aviation Administration.