CHICAGO -- President Bush, urging Americans to "get on the airlines," unveiled plans on Thursday to deploy National Guard troops at U.S. airports and make planes more secure after the Sept. 11 hijack attacks.
"Get on the airlines, get about the business of America," Bush told thousands of workers at Chicago's O'Hare airport, the second busiest U.S. airport.
"Everybody here who showed up for work at this important industry is making a clear statement, that terrorism will not stand," Bush said.
Seeking to allay Americans' fear of flying in the wake of the attacks -- which has led to widespread flight cancellation and more than 100,000 airline industry layoffs -- Bush said he would "dramatically increase" the number of armed federal marshals on commercial flights and work with Congress to put the federal government in charge of airport inspections.
He said the government would pay for the stationing of National Guard troops at airport inspection stations, to serve while the other new measures were implemented.
Bush spoke with an American Airlines and a United Airlines plane parked nose-to-nose behind him. "I think it's interesting that on one side we see American, on the other side it says United. Because that's what we are. America is united."
The measures were aimed at addressing security lapses laid bare by the attacks in which two hijacked commercial planes were crashed into the World Trade Center in New York, a third into the Pentagon outside Washington and a fourth into a rural area of Pennsylvania. Two were American Airlines flights; two were United .
Almost 7,000 people were dead or missing in the attacks.
The White House also confirmed on Thursday that Bush had authorized the most senior officers in his military chain of command to order the shooting down of any commercial airliner deemed to pose a threat to a population center.
White House spokesman Scott McClellan said the order would only apply as a last resort if the president could not be reached.
Bush said the government would set aside $500 million to fortify cockpit doors and would fund development of transponders, which signals the airline's whereabouts, that could not be switched off as well as cockpit video screens to monitor cabin activity.
He said he would work with Congress to put the federal government in charge of airport security and screening services.
While the new security will be performed by a mix of government and private workers, uniformed federal personnel will manage all operations and maintain a presence at the nation's 420 commercial passenger airports, the White House said in a fact sheet.
Among other things, the government will set new standards for airport security, supervise passenger and baggage security, test, train and carry out background checks on security personnel and oversee patrolling of secure airport areas.
Making only his second trip outside the Washington area since the attacks -- the first was to tour the damage in New York -- Bush and other U.S. officials were trying to revive confidence in the airline industry and the broader economy.
Transportation Secretary Norman Mineta flew coach on a United flight from Washington to Chicago to join Bush.
"He said the flight was just perfect," Bush said of Mineta's flight.
The U.S. economy, fragile before the tragedy, has taken a new hit with airlines laying off employees and warning of bankruptcy from plummeting ticket sales. The effect of reduced travel demand has rippled through other industries.
Saturday, Bush signed legislation bailing out major airlines to the tune of $15 billion, including $5 billion in direct assistance and $10 billion in loan guarantees.
That comes on top of $40 billion approved by Congress soon after the attacks to help cope with their aftermath, including $3 billion for airline security that will provide the new money to make cockpits more secure.
On his return to Washington later Thursday, Bush was to press his efforts to build an international coalition to join the United States in a "war on terrorism" in meetings with Prime Minister Guy Verhofstadt of Belgium and European Union President Romano Prodi.
