The nation's grounded commercial airlines will be allowed to resume limited travel today, according to Federal officials, but travelers will face slower operations and tight security. However it has not been determined if cargo that has been on the ground since Tuesday’s attacks will be able to continue to its destinations yet.

Transportation Secretary Norman Y. Mineta said commercial and private planes would be allowed to fly on a case-by-case basis effective 11 a.m. ET. He said passengers should call airlines to check flight schedules and service, and allow extra time to deal with new security procedures.

"There will be some inconveniences, but safety will be the first element of our system to be restored," Mineta said in a statement released by the White House.

At least for today, the only flights permitted by the Federal Aviation Administration are domestic and international flights that were diverted by Tuesday's government closure of U.S. commercial airports. Airlines are also being permitted to route empty planes to airports to ease planning of regularly scheduled flights.

The government said it could be several days before airlines return to anything close to regular service, which means LTL and truckload carriers that use airplanes as part of their service will most likely still have delays in their delivery service.