DALLAS (AP) -- More than 400 flights are expected to be canceled through early tomorrow morning as Delta Air Lines and American Airlines continue to inspect wiring bundles on some planes.

A Delta spokeswoman says the airline expects about 275 cancellations through tomorrow morning. American Airlines has also canceled 132 of its estimated 2,300 flights scheduled for today.

Delta is expecting heavy volume at its hub at Hartsfield-Jackson Atlanta International Airport. Both Delta and the Transportation Security Administration are bringing in extra staff to handle the crowd of travelers.

American says it began its inspections after an audit of the carrier by a joint team of inspectors from the Federal Aviation Administration and the airline, which canceled 325 flights yesterday.

However, an American spokesman says the airline expects all but a few of the inspected planes to be back in service tomorrow.