Many international flights to Turkey were cancelled Saturday despite efforts by the Ankara authorities to get life back to normal following an abortive coup attempt.
The US government said it had suspended all flights to Turkey, and banned all airlines from flying to the United States from Turkey due to uncertainty after Friday's failed coup.
Turkish authorities were seeking Saturday to resume business as usual and Istanbul's Ataturk International Airport -- shut down by the plotters -- was gradually reopening.
But international carriers were preferring to wait and see before resuming a normal service.
Along with their US counterparts, Russian airlines have suspended flights to Turkey although they were repatriating vacationers back home.
"President (Vladimir) Putin ordered the transport ministry and other agencies to properly inform passengers and organise their inbound flights from Turkish airports," Kremlin spokesman Dmitry Peskov was quoted as saying Saturday by the Interfax news agency.
British Airways cancelled all its Saturday flights to and from Turkey "in light of the events unfolding" there, a company spokeswoman said.
German flag carrier Lufthansa cancelled eight of its 10 flights scheduled between Germany and Turkey, including all flights to Ankara and Istanbul.
The two remaining flights were to the resorts of Bodrum and Antalya, a Lufthansa spokesman told AFP.
The airline announced later in the day that it would return to normal service from Sunday, as did its SWISS subsidiary.
In a statement Saturday the US Federal Aviation Administration said it had issued a notice "that prohibits all US commercial and private aircraft from operating into or out of any airport in Turkey. It also prohibits an aircraft of any registry from departing Turkey for the US.
The FAA said it was "monitoring the situation in Turkey in coordination with our partners in the State Department and The Department of Homeland Security and will update the restrictions as the situation evolves."
The US embassy in Ankara added that security "at Ataturk airport is significantly diminished and US government employees have been instructed not to attempt to travel to and from Ataturk airport."
It advised US citizens in Turkey "to seek shelter in safe places," avoid unnecessary travel, and monitor media reports.
The warnings remain in place even though Turkish airports reopened following President Recep Tayyip Erdogan's pre-dawn announcement of victory over the discontented army officers who mounted the bloody attempt to overthrow him.
Other smaller airlines were continuing their flights to southern Turkish resorts, with Easyjet and Thomas Cook saying they did not expect any changes to its schedules to places such as Antalya, Izmir and Rhodes.