In Lahore and Rawalpindi, the employees staged sit-in outside airport to press for their demands.
They said protest would continue until government accepted demands of the PIA Joint Action Committee.
At least 55 PIA flights were affected due to ongoing strike of the workers bring loss of billions of rupees to the national flag carrier.
The PIA employees were killed and several more wounded at Karachi’s international airport on February 2 when clashes broke out between security forces and staff, though authorities denied opening fire.
The strike continues despite prime minister’s warning the demonstration was illegal and those taking part could face up to a year in prison under a law that restricts union activity in state-administered sectors.