The largest air carrier in the United States, American Airlines, has canceled more than 1,000 flights Wednesday to conduct safety inspections of its aircraft.
The airline canceled nearly 500 flights on Tuesday.
American Airlines is inspecting - and if necessary rewiring - its MD-80 aircraft to comply with government safety regulations.
American uses that aircraft model on more than one-third of its flights.
The move comes after federal inspectors raised concerns about recent wiring inspections.
The Federal Aviation Administration has been looking more closely at airline compliance of federal safety rules.
Several U.S. carriers have grounded aircraft as a result of the government audit, which was triggered by inspection and maintenance lapses at Southwest Airlines.
Some information for this report was provided by AFP and Reuters.