Dhaka, Nov. 14 -- The United States has resumed departures after a nationwide ground stop halted most flights from taking off for more than four hours, triggering thousands of cancellations and delays.

The Federal Aviation Administration (FAA) imposed the safety measure on Nov 13 following a telecommunications failure affecting air traffic control facilities nationwide.

The restriction was lifted at 8:15pm Eastern Time, but airlines faced a lengthy recovery.

Here is what we know.

What Happened?

The FAA ordered a nationwide ground stop at 3:54pm after communications problems affected its 22 air route traffic control centres, which manage aircraft travelling between airports.

Most flights awaiting departure were held on the ground. Ai...