America.. The decision to stop flights has been lifted, but delays and cancellations are still continuing.. Here is what we know

More than 4 hours after all departing flights in the United States were halted - causing chaos in the travel sector across the country - the Aviation Administration lifted the nationwide take-off ban, on Saturday.

However, travelers will still face delays or cancellations to their flights, as well as long waits at airports; Officials warned that it will take some time for airports and airlines to return to full operational capacity.

Here's what we know and what we don't know yet:

• Why were planes prevented from taking off? The Aviation Administration announced a decision to ban all flights in the United States this afternoon. This decision requires aircraft to remain on the ground and prevent them from taking off. Note that there were more than 3,500 planes in the air at the time the decision was issued.

• What is the cause of this problem? US Secretary of Transportation Sean Duffy said that outdated air traffic control technology and routers that were subjected to massive data pressure were the reason behind the decision to prevent takeoff.

Earlier, the Aviation Administration informed the companies that the problem likely began at Chicago Midway International Airport, and then spread to the entire country.

• Was it a cyber attack? Homeland Security Secretary Markwayne Mullen confirmed that his department had found “no evidence” that the communications glitch that prevented the takeoff was a cyberattack. However, he noted that investigations are still ongoing, “so we will not completely rule out this possibility.”

• What is the effect size? Although Mullen assured that the safety of the public was not in danger, thousands of travelers across the country had a nightmare on their journeys.

According to FlightAware, an air traffic tracker, about 15,000 flights were delayed or canceled today, and more than 700 flights within, arriving at, or departing from the United States were canceled on Saturday. Airports continue to direct travelers to check the status of their flights through airline companies before heading to the airport. Many travelers now find themselves facing two options: either continue waiting or make alternative plans.

Passengers who got off one of the planes told CNN that they remained stranded on the airport floor for more than an hour and a half. • Lack of space at airports: With many planes unable to take off due to the complete cessation of flights nationwide, airports suffer from a shortage of gates and runway space needed to park planes.

A source at the airport reported that Ronald Reagan National Airport in Washington does not have enough space to park planes, and it can no longer receive alternative flights.

International unrest:

The European Air Traffic Control Authority (Eurocontrol) suspended all flights to the United States from the 42 member states at the request of the US Aviation Administration.

The suspension was scheduled to last until midnight EST. Flights to the United States from major airports in Asia were also affected by the disruption.