By now, we’re sure you’ve heard about the travel ban that President Trump recently called into effect. If you plan on traveling in the near future, here’s what you should know about it, according to Travel & Leisure:

“As President Donald Trump’s travel ban went into effect over the weekend, citizens and immigrants from seven countries—Iraq, Iran, Syria, Yemen, Sudan, Libya and Somalia—were not the only ones to experience its impact.

U.S. travelers saw a wave of immediate reaction that could continue to affect their own travel.

Here is what to expect if you are traveling soon.

Be ready for possible airport delays

Protests erupted at airports across the U.S. over the weekend as the ban took immediate effect. While there was little evidence that the protests caused travel delays, the demonstrations did affect ground transportation in and out of airports, especially JFK in New York City.

Travelers should check their local transportation providers for any disruptions in service. Before heading to the airport, research any possible demonstrations, closed roads, or other events that might be taking place near your terminal.

Give yourself more time

As confusion about the executive order and how exactly it is to be implemented continues, travelers should give themselves additional time at the airport. Particularly with international travel, it’s good to aim to arrive at the airport three hours before your scheduled departure.

Know which airlines are offering refunds

For anyone affected by the ban, American Airlines, Delta, and United have begun offering fee waivers, including rebooking and refund options.

To find out which options are available depending on flight and destination, air travelers should always check directly with the air carrier.

Double check you’re carrying the appropriate documents

Green card holders and visa holders should take extra precautions to ensure that they have all of the proper documentation in order to reenter the U.S., including a passport from their home country as well as their U.S. residence card.

The Department of U.S. Citizenship and Immigration Services offers more specific information concerning the necessary documentation on their website.

Visa holders should be prepared for secondary screenings

Over the weekend, customs officers also began detaining visa and green card holders who were originally from the seven countries included in the ban, according to human rights organizations. Dual citizens and green card holders from the banned countries were also frequently subjected to secondary security screening.

Secondary security screening can include pat-downs, being questioned in a separate “greenroom,” and being detained at the airport, as journalist John Walton detailed in a personal essay on his own experience.

Representatives from the Trump administration sent mixed messages about this aspect of the ban on Sunday, with some claiming the ban should not affect permanent residents while others warned that secondary screenings would continue to be in effect, CNN reported.

Be aware of your destination country’s views on the ban

Leaders from the U.K., Canada, France, and Germany—to name a few—all condemned the executive order.

Iran went further than condemning the ban and announced plans to bar U.S. citizens from entering the country, according to Reuters. This announcement came after relations between the two countries had thawed under President Barack Obama, whose administration had begun to resume business and tourism relations after decades of sanctions.

Be prepared for some uncertainty

A great deal of confusion surrounds the executive order’s implementation. How the rule applies to green card holders, for example, changed over the weekend.

Travelers should be prepared to encounter some uncertainty in the coming weeks.”