There will be lingering effects from the terrorist attacks that will affect American commerce for days, if not weeks or months.

Delays in mail service and package deliveries are now inevitable, and may last for some time.

News Specialist Stacey Butler has the story.

Bart Johnson, Mail Express: "THERE IS NO OVERNIGHT, THERE IS NO SECOND DAY, THERE IS NO GUARANTEE, BASICALLY THE ONLY THING THAT'S HAPPENING RIGHT NOW ARE TRUCKS."

Ask Bart Johnson with Mail Express just how long it will take to deliver express mail to and from the east coast, and this is probably answer you'll get:

"TO ANSWER THAT I HAVE TO ASK YOU A QUESTION--WHEN AM I ASSUMING THAT THE FAA IS PERMITTING FLIGHTS TO OCCUR? TODAY, TOMORROW, MONDAY?"

At this point cargo flights are still grounded and no one knows for sure when they'll resume.

But the longer Federal Express planes are grounded, the bigger the mail pileup.

"THE PLANE CAPACITY WAS NEVER MEANT TO HANDLE MULTIPLE DAYS OF BACKLOG."

The United States Postal Service is faring a little bit better. 75-80% of mail is transported by ground anyway.

In response to the terorist attacks Tuesday, the Postal Service hired an additional 6-thousand private carriers to deliver the mail.

Michael Maxfield: "WE CAN PROBABLY GET GROUND TRANSPORTATION TO ANYWHERE IN THE WEST IN A DELAY OF ONLY ONE DAY."

A Post Office spokesperson says Priority Mail that regularly takes 2 to 3 days is now going to take 3 to 4.

East Coast, expect at least a three day delay for all deliveries.

Michael Maxfield: "SO REALISTICALLY WHAT WE'RE LOOKING AT NOW IS MAYBE SEVEN TO TEN DAYS FOR SOME OF THOSE DESTINATIONS BACK EAST."

For mail delivery franchises like this, it's been a slow and tense three days.

Bart Johnson: "PEOPLE ARE SHELL SHOCKED. PEOPLE REALIZE THAT NOTHING IS ARRIVING ANYWHERE."

So when you hear--the check is in the mail--this time, it probably is.

The FAA is considering a permanent ban on mail, or any cargo, on any domestic flights at all, because it could pose a security risk.

While that remains under consideration, the US POST Office is still planning for the worst, in other words to rely heavily on ground transportation.