Both international and domestic air and train links were cut late Sunday in Belgium as a national strike began against the new government's austerity policies, official sources said.
"All flights are cancelled. Everything is immobilised until the same time tomorrow," Brussels Airport spokeswoman Florence Muls told AFP.
She added that a total of 600 incoming and outgoing flights would not land at or take off from Brussels airport in the 24-hour period that air traffic controllers would be on strike.
Officials at Charleroi airport outside the Belgian capital told AFP earlier that outgoing flights were cancelled and incoming ones would be diverted for 24 hours from 2100 GMT Sunday.
The other airports affected by the strike are those at Liege, Antwerp and Ostend.
Belgian rail firm SNCB said on its website that domestic train services were cancelled from 2100 GMT Sunday through Monday.
Eurostar said on its website that a train scheduled to travel late Sunday from London to Brussels would stop at the French city of Lille, near the Belgian border, and not travel on to the Belgian capital.
Eurostar said its services were also cancelled all day Monday.
Thalys said on its website meanwhile that trains serving Lille and Amsterdam as well as Amsterdam and Paris were cancelled Sunday evening.
Its services to the Netherlands, France and Germany were cancelled through Monday, including disruptions early Tuesday.
On Monday the strike will widen to bus, tram and metro services as well as schools, businesses, factories and government offices throughout Belgium.
The movement began last month with a 100,000-person march in Brussels that ended in clashes leaving 112 police officers injured.
Belgian unions oppose a decision by Prime Minister Charles Michel's right-of-centre coalition government to scrap plans for a usually automatic cost-of-living raise next year.
They also reject public sector cutbacks and plans to raise the retirement age.