US government agency Federal Aviation Administration (FAA) closed airspaces over Venezuela and in the Caribbean "due to safety-of-flight risks associated with ongoing military activity".
US and UK airlines began cancelling flights early on Saturday (3 January) after Venezuelan leader Nicolas Maduro and his wife Cilia Flores were captured and flown out of the country.
The FAA cautioned British airlines against "potential risk from anti-aircraft weaponry and heightened military activity" if flying within 100 miles (160 km) of Venezuelan airspace, according to news agency Reuters.
P&O Cruises confirmed 5,000 passengers, a mix of inbound and outbound guests, were impacted by international air restrictions which have now been lifted.
Tui was forced to cancel a number of charter flights it was scheduled to operate for the line, leaving P&O Cruises to arrange new flights for passengers on Arvia, which is based in the Caribbean.
The line's spokesperson said: "P&O Cruises has worked tirelessly over the weekend with our charter carriers to arrange new flights for a total of 5,000 guests.
"The onward ports of call and itinerary are being prioritised and communicated to all guests onboard so they can now continue with their planned holiday.”
Princess Cruises' Grand Princess ship's departure from San Juan was delayed until Monday (5 January) as a result of flight cancellations in and out of Puerto Rico.
More than 300 flights at San Juan's Luis Munoz Marin International Airport have been axed, affecting nearly 50,000 passengers, according to local media reports.
A Princess spokesperson said: "As a result, we will no longer call to St Thomas on 5 January and will instead proceed directly to St Kitts for our scheduled arrival on 6 January.
"Each guest will receive a prorated refund equivalent to one day of their cruise fare, including taxes and fees, and any onboard packages purchased."
The spokesperson added: "We will continue to keep a close eye on the region and stay tightly connected with trusted local and regional authorities and global security experts to make thoughtful, informed decisions, always prioritising safety."
Windstar Cruises confirmed turnaround operations in St Maarten and Bridgetown airports have been impacted. A Windstar spokesperson said: "We have secured a berth to delay departure, allowing flexibility for guests experiencing flight delays."
It added that its Wind Surf and Wind Spirit ships would depart on Monday.
