WASHINGTON, May 31 (Reuters) -

The National Transportation Safety Board said on Friday it

will open an investigation into a near-collision earlier this

week between an American Airlines ( AAL ) jet and a small

airplane at Reagan Washington National Airport.

The Federal Aviation Administration said earlier that an air

traffic controller on Wednesday had canceled takeoff clearance

for American Airlines Flight 2134 - an Airbus A319 -

because a Hawker Beechcraft Super King Air was cleared to land

on an intersecting runway at the airport. Reagan has the busiest

runway in the nation.

"We will thoroughly investigate," FAA Administrator Mike

Whitaker said on Thursday.

American Airlines ( AAL ) said on Friday "the safety of our

customers and team members is our top priority, and we're

grateful to our crew for their professionalism. We will support

the FAA and NTSB in their investigations."

The NTSB has opened investigations into more than a half

dozen near-miss incidents since January 2023 that raised

concerns about U.S. aviation safety and the strain on

understaffed air traffic control.

A persistent shortage of controllers has delayed flights

and raised

safety concerns

. At many facilities, controllers are working mandatory

overtime and six-day weeks to cover staffing shortages. The FAA

wants $43 million to accelerate hiring and training of

controllers and has

sought to impose new rest

requirements.

Staffing issues

forced the FAA to extend cuts

to minimum flight requirements at congested New York

City-area airports through October 2024 - allowing airlines to

fly fewer flights without forfeiting take-off and landing slots.

Airlines have

asked for the waiver

to be extended by another year.

The NTSB will hold a June 6 hearing to determine the

probable cause of a February 2023 near-miss incident involving a

FedEx cargo plane and a Southwest Airlines jet in Austin, Texas.

The two planes nearly collided when the FedEx Boeing 767

was forced to fly over the Southwest jet to avoid a crash in

poor visibility conditions. NTSB Chair Jennifer Homendy said

last year the planes came within about 115 feet (35 meters) of

each other in what could have been a "terrible tragedy."