Ankara is threatening military raids against PKK bases in northern Iraq unless Baghdad and Washington act to end the group's safe haven in the area.
Turkish officials say at least 3,500 PKK fighters are based in the mountains of northern Iraq.
Ankara has sent 100,000 troops to its southern border with Iraq in readiness for what many believe will lead to a raid against PKK bases.
A Turkish incursion would also put the United States in an awkward position with key allies: Nato-member Turkey, the Baghdad government and the self-governing Iraqi Kurds in the north.
Washington has been pressing Turkey for restraint, while pushing for more action by Iraqi Kurds to crack down on rebel bases.
Ali Babacan, Turkey's foreign minister, earlier said that Ankara had started imposing some sanctions against northern Iraq, but gave no details.
"We have from time-to-time restricted flights on technical grounds, this might happen again," Babacan told a press conference.
A travel agent in Ankara told the AFP news agency that a flight ban had been imposed on at least two airlines operating flights from Istanbul to Irbil and Sulaimaniyah, northern Iraq.
On Wednesday, Turkey's cabinet approved economic sanctions against groups deemed to support the outlawed PKK.
"I cannot discuss the measures we are thinking of. The measures are directed against the PKK and those that directly support them," Cemil Cicek, Turkey's deputy prime minister said.
One of the possible measures is a flight ban along with restrictions on traffic through the Habur border gate with Iraq, Turkish newspapers have reported.
Curbs on exports to northern Iraq and a freeze on the operations of firms in Turkey belonging to Masoud Barzani, leader of the autonomous Kurdish administration in Iraq, are also understood to be under consideration by Turkey.
On Tuesday, aviation officials told Reuters that Turkey's civil aviation authority had imposed limits on an Istanbul-based charter airline.
Tarhan Tower has been refused permission to fly two of its three weekly flights to Irbil in Iraq this week.
The United States uses Turkey's Incirlik airbase to provide logistical support to its forces in Iraq, though it has very few troops in the north of Iraq.
Condoleezza Rice, the US secretary of state, will discuss the PKK issue with Turkish leaders in Ankara on Friday.
More than 37,000 people have died due to violence between Turkey and the PKK since the separatist group started its campaign in 1984.