CNN  — 

Two US airlines fly the 737 MAX 8 – the type of jet that crashed last year in Indonesia killing 189 people and on Sunday in Ethiopia killing all 157 on board.

American Airlines – which flies 24 of the new planes – said in a statement to CNN on Monday that it is monitoring the investigation in Ethiopia and following last year’s Federal Aviation Administration directive after the crash in Indonesia of Lion Air Flight 610.

The airline “continues to collaborate with the FAA and other regulatory authorities” and it has “full confidence in the aircraft,” the statement said.

The crashes of two new jets during such a short time period has focused extraordinary attention on the 737 MAX 8, its operators and national regulators – so much so that Ethiopian Airlines, China and Indonesia have grounded all planes of that type, nationwide. In the Caribbean, Cayman Airways has decided to ground its 737 MAX 8s.

Southwest – which includes 34 737 MAX 8s in its fleet – said in a statement it doesn’t plan to change its operational policies or procedures and it remains confident in the safety of its entire fleet. “We have been in contact with Boeing and will continue to stay close to the investigation as it progresses,” Southwest said in the statement.

Jemal Countess/Getty Images
A woman lays on the coffin of her loved one during a memorial service on March 17 for the Ethiopian passengers and crew who died in the Ethiopian Airlines crash. All 157 people aboard the Boeing 737 Max 8 died when the flight went down six minutes after taking off from Bole Airport.
Samuel Hathab/AFP/Getty Images
Coffins of victims of the Ethiopian Airlines crash are gathered during a mass funeral at Holy Trinity Cathedral in Addis Ababa, Ethiopia, on March 17. The crash has resulted in the worldwide grounding of the Boeing 737 MAX 8 aircraft model involved in the disaster.
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A mourner screams for a loved one who died in the Ethiopian Airlines crash during a memorial service at Holy Trinity Cathedral on March 17, in Addis Ababa, Ethiopia.
Minasse Wondimu Hailu/Anadolu Agency/Getty Images
A mass funeral ceremony is held for victims of the Ethiopian Airlines crash at the Holy Trinity Cathedral in Addis Ababa, Ethiopia on March 17.
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Relatives of Kenyan victims, who were among the 157 passengers and crew killed on the crashed Ethiopian Airlines flight, light candles during a memorial service at the Kenyan Embassy in Addis Ababa, on March 16.
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Debris including a charred part of an onboard safety instruction card is seen at the crash site of an Ethiopian Airlines flight on March 16, at Hama Quntushele village near Bishoftu in the Oromia region.
MICHAEL TEWELDE/AFP/Getty Images
A crowd gathers near debris at the crash site of Ethiopian Airlines Flight ET302 on Monday, March 11.
Mulugeta Ayene/AP
People work at the crash site on March 11.
Samuel Habtab/AP
Mourners attend a memorial service in Addis Adaba, Ethiopia, on March 11.
Mulugeta Ayene/AP
A passport lies on the ground at the scene of the crash.
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Emergency workers move around body bags on Sunday, March 10.
Mulugeta Ayene/AP
Relatives of the victims react at Bole International Airport on March 10.
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Residents of Bishoftu, Ethiopia, collect plane debris.
Tiksa Negeri/REUTERS
Personal effects are strewn on the ground at the crash site.
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Wreckage is recovered at the scene of the crash.
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People watch workers at the wheat field where the plane crashed.
Yidnek Kirubel/AP
A piece of the wreckage lies on the ground.
Jemal Countess/Getty Images
A recovery crew works at the scene on March 10.
Mulugeta Ayene/AP
A victim's family member reacts as she speaks on a phone at the airport in Addis Ababa.
Ethiopia Airlines/HANDOUT/EPA-EFE
A handout photo made available by Ethiopian Airlines shows the airline's CEO, Tewolde GebreMariam, standing among debris at the crash site.
TIKSA NEGERI/REUTERS
People walk past a piece of the wreckage.

It’s very early in the investigation. Because the flight data recorder and cockpit voice recorder were only recovered Monday, the two crashes have not been directly linked. There are countless reasons a plane can crash – including birds flying into engines, a problem with weight balance or pilot error.

“This is all so premature,” said John Gogila – former National Transportation Safety Board member. “What I would offer is a word of caution. We need to get the data analyzed first and then decide how to move forward.”

Goglia said airlines that fly the 737 MAX 8 should be reviewing their flight training for the aircraft.

‘Behind the scenes at airlines’

“You can’t underestimate the power of what goes on behind the scenes at airlines,” said William Voss, a former FAA deputy director and ex-CEO of the Flight Safety Foundation. “If they think they have a threat, they will step up and respond independently.”

Investigators in the Lion Air crash suspect the crash was caused by an angle of attack (AOA) sensor on the outside of the plane which transmitted incorrect data that could have triggered a kind of auto-pilot system called the Maneuvering Characteristics Augmentation System (MCAS) that forced the plane’s nose down.

Voss said he thinks airlines that fly the 737 MAX 8 have been “doubling up on inspections of sensors” and making sure all pertinent information about the plane has been communicated to pilots. “And I would be in continuous communications with Boeing,” Voss said.

In November Boeing issued an “Operations Manual Bulletin” advising airline operators how to address erroneous cockpit readings. It pointed airlines “to existing flight crew procedures to address circumstances where there is erroneous input from an AOA sensor,” a Boeing statement said. The FAA later issued its own emergency airworthiness directive that advised pilots about how to respond to similar problems.

02:14 - Source: CNN
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Voss also warned against rampant speculation about the investigation and allowing social media to drive it. “Social media has changed the way we see the world but nothing has changed the reality and physics of human error,” he said. “So we can’t let social media drive decisions about reality.”

United Airlines flies a different version of the 737 MAX – the 737 MAX 9. It currently has 14 in its fleet. Although there are no reports that MAX 9s have had any trouble with their AOA sensors, the FAA included that type of plane in its November emergency directive.

How to know if you’re booked on a 737 MAX 8

For passengers, there are three fairly simple ways to know if you’re booked to fly on a 737 MAX 8.

1. Check your airline site or app. Clicking on the flight number will show you what type of airplane is assigned to the flight.

2. Check the registration of the airplane on the FAA site. Before you board, note the registration number which is clearly marked on the side of the plane. Plug that number into the FAA registration data base here.

3. Aviation apps such as FlightRadar24 make it easy to see the type of airplane on which you’re scheduled to fly. Look up your flight number or use the app filter function to track all 737 MAX 8s and any other aircraft.

CNN’s Kara Fox contributed to this report.