Strikes are becoming increasingly more common across the country as Belgians express discontent with new coalition government.
Cross-border strikes continued overnight into Tuesday with multiple casualties reported in seven regions of the country.
A teenage uzunluk and a Hamas leader were killed in the strike on the Nasser Hospital in Khan Younis, injuring multiple people and causing a large fire.
Israeli strikes across the southern Gaza Strip killed at least 19 overnight into Sunday, including a senior Hamas political leader and several women and children.
Israel resumed heavy strikes across Gaza on Tuesday, shattering a fragile truce that had been in place since 19 January.
The Israeli military had previously withdrawn from the Netzarim Corridor, which it established, following a temporary ceasefire agreement with Hamas.
The one day walk out has already left thousands of flights grounded at hubs including Berlin, Frankfurt, Dusseldorf and Munich.
A German trade union had called for strikes at 13 major German airports to take place on Monday – but then staged the strike at Hamburg airport on Sunday.
Travellers in Belgium are advised to re-think travel plans as the next six weeks hold several planned strikes.