U.S. travel officials, airlines and law enforcement officials are on alert after a bombing at the check-in zone of Brussels Airport and the Belgian capital's subway killed at least 31 people Tuesday.
The Transportation Security Administration is checking on the safety of federal air marshals who were on duty at the Brussels airport Tuesday morning or on inbound or outbound flights.
The border between France and Belgium was closed and all Eurostar train service to Brussels was halted.
However, as long as passengers weren't trying to get to Brussels, the actual ripple effect on travel appeared to be minimal with few slowdowns for American skies.
