Updated: 3:45 p.m. EST

Officials at Houston’s two airports, William P. Hobby and George Bush Intercontinental Airport announced they would be resuming limited flight operations at 4 p.m. CST and that they expected full service to be restored by the weekend.

According to a post on Hobby Airport’s Facebook page, travelers should contact their carriers to determine whether their flight will operate. Earlier Wednesday, United Airlines announced it had canceled all flights through noon Thursday.

With many Houston-area roads still unsafe for travel, officials also said that only those with confirmed reservations should come to the airports. They also urged people to use caution when traveling to the airport.

Earlier post: 

Houston’s two major airports remain shuttered to commercial traffic Wednesday and airlines announced they have extended fee waivers as the city and state struggled to recover from historic storms and widespread flooding. More than 32,000 people are in shelters and thousands more are staying with family and friends.

Officials at George Bush Intercontinental Airport, a hub for United Airlines, said that while water has begun to recede from roads, commercial flight operations remain suspended there and at William P. Hobby Airport until further notice. Both airports shut down Sunday.

According to the flight tracking website, FlightAware.com, on Wednesday, more than 1,100 flights to and from Bush Airport were canceled; just over 320 were canceled into and out of Hobby Airport. A similar number of Thursday flights from both airports are also canceled. However, FlightAware lists fewer cancellations for Friday, indicating that the airports could possibly resume some operations by the end of the week.

United Airlines said that flights to and from Bush Airport are canceled until at least noon Thursday. It has also expanded travel waivers to include airports in Louisiana, including Alexandria, Baton Rouge, Lafayette, Lake Charles, New Orleans and Shreveport. The airline also expanded the time period for which fees will be waived to include flights departing through Nov. 15.

American Airlines, which is based in Fort Worth, also expanded travel waivers to include several airports in Louisiana and said change fees may be waived for flights previously ticketed through Sept. 7 for rescheduled travel through Sept. 20. Southwest Airlines, which in based in Dallas, has also suspended flights to and from Houston Hobby, and urged travelers not to attempt to get to the airport until told by local authorities that it is safe to travel.

Emirates also announced it had canceled flights to and from Bush  through Thursday. More details here. 

FAA officials also continued to warn drone operators to stay out of affected areas out of concern they would interfere with rescue and recovery missions.

Airports officials noted that even when airports reopen, travelers may still encounter problems traveling roadways to and from airports.  Relief efforts have been hampered by lack of passable roadways. Harvey flooded more than on quarter of Harris County, where Houston is located. In addition, search and rescue operations continue throughout the region.

On Tuesday, U.S. Transportation Secretary Elaine Chao announced $25 million in emergency relief funds for Texas to aid the state in its efforts to repair roads and bridges.

“I have mobilized the Department of Transportation to provide whatever assistance Texas requires to restore the state’s transportation systems,” Chao said in a news release announcing the release of funds. “The funding provided today will help the state to act immediately and represents the beginning of our commitment to help repair Texas’ affected infrastructure.”

According to DOT, the emergency funds will be targeted at the most “critical repairs” to roadways and bridges over the next few weeks.

Even with the devastation, airport officials remain optimistic.