* Passengers face hours-long waits in security lines

* LaGuardia collision kills two, injures several, causes

flight cancellations

* ICE agents deployed to airports for crowd control,

potential arrests

* Airlines face rising fuel costs, cut flights amid

budget standoff

By Jayla Whitfield-Anderson, David Shepardson and Andy

Sullivan

NEW YORK/ATLANTA/WASHINGTON, March 23 (Reuters) - The

strained U.S. air-travel system was stretched even further on

Monday after two pilots died in a runway accident that shut New

York's LaGuardia Airport and President Donald Trump deployed

armed immigration agents to help with hours-long lines that have

cropped up at security checkpoints nationwide.

The crash between an Air Canada Express jet and a fire truck

at LaGuardia injured dozens of passengers and led to hundreds of

flight cancellations at the start of the working week, the

latest disruption for airports and carriers already contending

with a weeks-long budget standoff in Congress and surging fuel

costs.

Travelers have endured hours-long waits at security screening

checkpoints in recent days as absentee rates have spiked among

Transportation Security Administration employees who have gone

without pay for more than a month. Hundreds of people were lined

up on Monday at some of the nation's busiest airports, including

Los Angeles and Atlanta.

"If the leadership was right we wouldn't have circumstances

like this," Atlanta resident John Edwards told Reuters as he

waited at the city's airport, where 42% of TSA agents were

absent on Sunday.

ICE DEPLOYED TO AIRPORTS

On Monday morning, U.S. Immigration and Customs Enforcement

agents wearing flak jackets and pistols stood guard in airports

in Atlanta, New York and New Jersey, according to Reuters

witnesses. They were not wearing masks, which they had done

regularly while carrying out Trump's immigration crackdown in

major cities.

Authorities said the agents would provide crowd control, but

Trump said they would also make arrests - raising concerns that

the chaotic raids that have played out on the streets of

Minneapolis, Chicago and elsewhere might come to the nation's

airports as well.

"They're able to now arrest illegals as they come into the

country. That's very fertile territory," Trump told reporters.

In Washington, there was little sign that the standoff between

Trump's Republicans and opposition Democrats would end soon.

Democrats have refused to fund the Department of Homeland

Security without new curbs on immigration agents, who have

killed U.S. citizens and sparked public outrage during their

crackdown. Though the White House has engaged in talks, Trump

said Monday he would not sign off on any compromise until

Congress first passed a series of voting restrictions that

Democrats have rejected, adding another potential roadblock to a

deal.

Airlines are also facing rising fuel costs, which have spiked

since the U.S. and Israel attacked Iran more than three weeks

ago. United Airlines said Friday it would cut flights through

the busy summer travel season, citing elevated oil prices.

A separate 35-minute ground stop at nearby Newark Liberty

International Airport on Monday morning added to delays after

air-traffic controllers evacuated their tower because of a

burning smell from an elevator, the Federal Aviation

Administration said.

LAGUARDIA COLLISION KILLS TWO, SEVERAL HOSPITALIZED

In New York, the pilot and first officer of an Air Canada

Express jet were killed when the plane collided with a fire

truck while it was landing, while another nine people were

hospitalized with serious injuries. The CRJ-900 plane, operated

by regional partner Jazz Aviation, had been carrying 72

passengers and four crew members. Some 572 flights were

cancelled, more than 50% of LaGuardia's daily total.

U.S. aviation has faced a chronic shortage of air traffic

controllers, but it was not immediately clear what led to the

crash, and Transportation Secretary Sean Duffy and other

officials were traveling to New York to investigate. Air-crash

investigations typically find that accidents result from

multiple contributing factors, rather than a single cause.

Kathryn Garcia, executive director of the Port Authority of

New York and New Jersey, said the fire truck was responding to a

separate aircraft that had reported an "issue with odor."

According to air traffic control audio, a controller can be

heard telling the craft that a fire truck was en route and

clearing a truck to cross a runway. Moments later, the

controller can be heard saying: "Stop, stop, stop, truck 1 stop,

truck 1, stop."

On Monday morning, the Air Canada ( ACDVF ) jet could be seen on the

runway, surrounded by emergency vehicles, its crushed cockpit

pointing skyward.