Express carriers UPS and FedEx Express said today they will resume their air operations tonight. The Federal Aviation Administration allowed commercial air traffic to resume today, 48 hours after hijackers used four commercial airplanes to commit terrorist attacks on New York City and Washington, DC.

UPS said it expected to run a "full up" air operation tonight and as a result, would deliver almost all of its backlog of Next Day Air express packages by Friday morning. All other air packages will be delivered by early next week.

"We've kept most of the air packages moving via our ground network the last two days so we've had a good headstart,” said UPS chairman and CEO Jim Kelly.

On disaster relief efforts, Kelly said UPS already is working with federal and national relief organizations as well as community leaders to coordinate the movement of supplies. Individuals interested in assisting should contact those organizations, such as the American Red Cross.

FedEx Express and FedEx Ground are making pickups and deliveries except in those areas in Manhattan and Washington, DC where access continues to be restricted. We are unable to predict when services to and from Manhattan will be resumed. FedEx Express Money Back Guarantee will be reinstated once operations return to normal.

However, FedEx said only limited transborder operations between the U.S., Canada and Mexico are occurring at present. Flights to and from the U.S. will be reinstated when permitted by the FAA.