Air traffic controllers across the country on Tuesday morning embarked on a two-day warning strike.
The warning strike is a prelude to a total industrial action scheduled to begin next week.
SaharaReporters gathered that flights were not disrupted at airports nationwide but they were experiencing some delay.
The strike action is coming a day after the death of an air traffic controller, Aniekan Effiong, who slumped at the Nnamdi Azikiwe International Airport in Abuja.
Effiong, who was until his death, an Assistant General Manager, Operations, with the Nigerian Airspace Management Agency, was said to have died at the Abuja station of the agency around 4am on Monday.
It was learnt that he resumed work on Sunday evening and was supposed to close on Monday morning before he experienced breathing difficulty and passed on.