The United States lifted airspace restrictions over the Caribbean late on Saturday after barring commercial flights during a US military operation that led to the capture of Venezuelan President Nicolas Maduro.
Maduro and his wife were flown by helicopter to New York City, where they face drug-trafficking and weapons charges.
They were seized by US special forces during a pre-dawn attack in which air strikes pounded sites in and around the Venezuelan capital Caracas late on Saturday.
US Transportation Secretary Sean Duffy said in a post on social media platform X that the initial restrictions expired at 12am (0500 GMT), when flights could resume as scheduled.
"Airlines are informed, and will update their schedules quickly," Duffy said.
The US Federal Aviation Administration (FAA) notified commercial airlines on Saturday to avoid Caribbean airspace, citing a "potentially hazardous situation”.
The notice said the closure was issued due to "safety-of-flight risks associated with ongoing military activity”.
Key carriers United Airlines, American Airlines , Spirit and Delta were readying to resume flights to the Caribbean.
In a statement, United said a flight to San Juan in Puerto Rico was planned for Saturday night, adding: "We expect to operate most scheduled flights to the region."
Delta Air Lines expects to fly its normal Carribean schedule, it said in a statement, but adjusted to reposition resources.
American Airlines said in a statement that it was preparing for the Eastern Caribbean airspace to reopen and had added more than 3,700 extra seats to and from the region on top of resuming scheduled service.
It said it was operating extra flights and deploying larger aircraft, including widebodies, to "add as much lift as possible" to help customers affected by the FAA-mandated closure.
Spirit Airlines said in an e-mailed statement that it had resumed flights to and from the Caribbean on January 4, following the expiration of the FAA's airspace closure directive.
Even after the removal of curbs, however, airlines will need several days to restore normal operations, said airline analyst Robert Mann, adding: "They have a day's worth of passengers basically" already stranded in the Caribbean.
American Airlines, Delta, United, Frontier Airlines, Spirit Airlines and JetBlue Airways began cancelling flights, in line with the FAA airspace closures in the Caribbean.
JetBlue canceled 215 flights, an airline spokesperson said.
The company said Sunday that it would resume normal operations.
Several European and South American airlines also canceled flights.
Air Canada said its Caribbean and South American operations were normal, under guidance from Transport Canada, and it was monitoring the situation, adding: "We will update as required if the situation changes."
