Authorities say an airline pilot who seemed to smell like alcohol was making pre-flight checks in the cockpit when police arrested him on a DUI charge.

A Southwest Airlines pilot was arrested Wednesday at a Georgia airport just before takeoff and accused of driving under the influence, according to airline officials and authorities in Georgia.

A pilot on a Southwest Airlines flight was walked off the flight by police officers and arrested for allegedly showing up for the flight intoxicated. David Paul Allsop, 52, was arrested by airport police in Savannah just before he was supposed to pilot a Southwest flight from Savannah/Hilton Head Airport in Georgia to Chicago-Midway on Wednesday morning.

A Southwest Airlines pilot was removed from the cockpit ahead of a Wednesday flight from Georgia to Chicago and was booked on a charge of driving under the influence, a source familiar with the incident told CBS News.

David Allsop, 52, is charged with driving under the influence, according to Chatham County Sheriff's office jail records.

The U.S. Department of Transportation sued Southwest Airlines Wednesday, alleging it illegally operates flights that are persistently delayed, harming passengers and fair competition in the airline industry.

The lawsuit alleges Southwest illegally operated chronically delayed flights and disrupted passengers' travel plans.

The DOT filed a lawsuit against Southwest Airlines, citing a pattern of chronic delays, as the government pushes for stricter accountability.

The U.S. Transportation Department is suing Southwest Airlines and has fined Frontier Airlines over "chronically" delayed flights, disrupting passengers' travel and plans.