With limited resources and thousands of flights with which to concern themselves each day, the Department of Homeland Security (search) has taken an unusual step to protect travelers flying the skies.

The government announced Tuesday that it has decided to recruit Secret Service (search) and Immigrations and Customs Enforcement (search) officers to share air marshal duties while those agents are already flying as part of their normal course of business.

"The future in law enforcement is to be joint. We have to be joint at all levels, and we have to be able to utilize the resources of each organization to be able to continue this war on terrorism," said Thomas Quinn, director of the Federal Air Marshal Service (search).

Since Secret Service and Customs agents take tens of thousands of flights for business each year and are already trusted federal agents, DHS officials decided to coordinate their travel schedules so that air marshals will be diverted from flights where Secret Service and Customs agents are already expected to be present.

That way, air marshals won't overlap on flights with other federal agents, and can be deployed to protect other routes.

In all, an additional 10,000 federal agents will be available to expand the safety net across the skies without actually being pulled away from their regular duties.

"We believe DHS is exhibiting leadership by best utilizing federal resources," said Liz Tobias, Republican spokeswoman for the House Select Committee on Homeland Security. This program will allow more passengers to fly safely, and will provide a better distribution of resources, she said.

"Today's agreement between the Federal Air Marshal Service and the Secret Service appears to be a positive change in policy that will provide the increased flexibility needed for air marshals to cover an expanded range of flights," said Rep. Edward Markey, D-Mass., a senior member of the Homeland Security Committee.

However, Markey added that he has other concerns about security in the air.

"While I welcome this new initiative, I question why the Bush administration has cut funding for the Federal Air Marshal program, an essential part of our layered aviation security strategy.  As Congress considers the administration's budget in the months to come, I will call for an increase in funding for this critical program," Markey said.

President Bush's proposed fiscal year 2005 budget for the Department of Homeland Security offers an 8.9 percent boost to $31.4 billion. The increase primarily comes from grants to first responders, increases to FBI counterterrorism programs, more money for ICE and funds to enhance aviation and transportation security to improve baggage screening equipment and efficiency. 

The 2004 fiscal year Homeland Security budget, the first ever, cost $30 billion and included $4.2 billion for first-responder programs, $9 billion for border protection and $5.2 billion for the Transportation Security Administration (search) and the Federal Air Marshal Program (search).

Already, ICE and Secret Service agents in flight are on the lookout. Michael Garcia, assistant secretary of U.S. Immigrations and Customs Enforcement, told Fox News that at least one customs official has been pressed into action.

"Within the last six months or so, we had an ICE agent called upon to respond to an unruly passenger on a flight from Hawaii into, I believe, the East Coast," Garcia said.

As part of the plan, Secret Service agents — who have extensive firearms training — will receive a special security briefing. Their future flight information will also be sent to the air marshals' Missions Operation Center, which functions out of a secure and secret location near Dulles Airport outside Washington, D.C. The center will coordinate travel details, borrowing from rosters of Secret Service and ICE schedules in order to place their agents on different flights.

"Partnerships in the truest form involve information-sharing, open communications and most critical — mutual trust," said Danny Spriggs, deputy director of the U.S. Secret Service.

Officials say the hidden facility is the center of gravity for the air marshal program. Not only does it track flights, but it passes on real-time threat information to marshals on the job. The operations center determines which flights are to be covered by air marshals, based on intelligence reports and other requirements.

Officials won't say how many potential incidents in the air they have disrupted, but note it is significant another domestic hijacking has not happened since the Sept. 11, 2001, terror attacks.

Fox News' Catherine Herridge and Peter Brownfeld contributed to this report.