...officials said on Tuesday.
The action will reduce the number of flights over the ex-communist EU member on Thursday, but it will have no impact on flights to and from main airports in Bratislava and Kosice, navigation provider Slovak Air Traffic Services (LPS) said.
LPS said some 50 out its 120 controllers would take part in the strike.
"We will strike mainly because safety is decreasing due to lack of people, especially in summer when there is lots of work." said Pavel Bugar, spokesman of the Slovak Association of Air Traffic Controllers. "It is not about wages."
The strike is expected to start at 10 a.m. (0900 GMT) on Thursday and last for two hours, Bugar said. He said controllers would stop working again at 5 p.m. for an undefined time if their demands were not met.
The LPS said it would try to ensure that flights between Vienna and Budapest, the capitals of neighbouring Austria and Hungary, were not affected by the strike.
The Transport Ministry said it did not consider safety situation as serious as described by the controllers, but added it was ready for talks to prevent the strike.
[BRATISLAVA/Reuters/Finance.cz]