A spokeswoman confirmed to CNN that Brussels Airport will be closed to passenger traffic at least through the weekend.
Tensions have remained high following Tuesday's bomb attacks, claimed by terror group ISIS, in which 31 people died.
Two bombs targeted the airport while a third hit the city's Maelbeek metro station.
The incidents prompted the U.S. State Department to issue a warning to its citizens in Europe.
U.S. citizens traveling to and throughout Europe were advised that "terrorist groups continue to plan near-term attacks" in the region, possibly targeting sporting events, tourist sites, restaurants and transportation.
"U.S. citizens should exercise vigilance when in public places or using mass transportation," the alert, issued March 22, says.
"Be aware of immediate surroundings and avoid crowded places. Exercise particular caution during religious holidays and at large festivals or events."
Security has tightened at European airports, and U.S. cities and airports have ramped up security
Warnings have been issued by officials in other countries, including Australia, the Netherlands, Canada, New Zealand, the Philippines, Hong Kong and India.
A temporary warning against travel to Belgium was lifted by the UK on Wednesday.
"In terms of travel advice, we continue to advise people to follow the advice of the Belgian authorities. Therefore we are no longer advising against travel to Brussels.
"British nationals in Belgium should remain alert and vigilant, stay away from crowded places, and follow the instructions of the Belgian authorities," says a statement released by the UK Prime Minister's Office.
While Brussels Airport remained closed to passengers, cargo flights and private flights resumed Wednesday evening.
The airport said it's working closely with airlines to help passengers find suitable solutions.
Travelers can now retrieve hand luggage and checked-in luggage from certain aircraft that were on the tarmac at the time of the Tuesday attacks.
A full list of the flights affected is here
There's also a lost luggage form available on the Brussels Airport website
Some areas of airport parking are open for travelers to pick up cars which were left at the site on Tuesday.
Here's the latest update on Twitter.
Brussels public transport
Meanwhile, select public transportation services in Brussels have resumed.
The city's metro service is running limited service, with the latest details available on the system's website
Some tram and bus services are operating.
European rail provider Eurostar said on its website
that it's running regular services on its Brussels route, though passengers wishing to cancel or postpone bookings can do so free of charge.
Paris's Gare du Nord station -- from which Eurostar services leave for London -- was evacuated Tuesday afternoon following the discovery of an abandoned suitcase.
The station has reopened and police in Paris confirmed to CNN that the security alert was a false alarm.
Lufthansa, Air France, KLM, British Airways, American Airlines, All Nippon Airways, United Airlines, Delta Airlines, Ryanair, Alitalia, Jet Airways and Easyjet are some of the airlines that canceled or diverted flights.
Aegean is offering free rebookings or full refunds to any passengers who want to cancel their Brussels flights between now and March 31.
Air Malta is waiving re-booking fees for customers with flights to and from Brussels Airport, up to March 24.
Many other airlines are offering similar options to affected travelers.
More updates about European and U.S. flights and policies are available here