By Christina Zdanowicz, CNN

After hearing about Boeing 737 Max 8 planes being grounded in other countries, one passenger frantically looked to find what plane she would be on.

It wasn't until Jenny Meads boarded Southwest Airlines Flight 2390 on Wednesday in Oakland that she learned she was on a Max 8 plane, according to Flight Radar 24 and the FAA. She said she was "nervous" and only became aware of it when she saw the plane's pamphlet in the seat pocket.

"When we got back into airspace where our cells would turn on, I started getting these alerts on all the news stations that I have saying that they have been grounded," she told CNN's Martin Savidge after landing in Atlanta.

Meads learned the Federal Aviation Administration had grounded all Boeing Max 8 and 9 planes because of similarities between Sunday's crash in Ethiopia and the Lion Air crash in Indonesia.

Boeing said "safety is a core value" and supported the FAA and the Trump administration's decision.

"I think it is the right choice, I mean what if God forbid, another one happens? They need to figure it out first for everybody's sake," Meads said.

What it was like to be a passenger on one of these planes

CNN affiliate KPRC reporter Vincent Crivelli tweeted from United Airlines Flight 1815 on a Boeing 737 Max 9 plane that was flying from Houston to San Francisco, according to Flight Radar 24 and the FAA. He noted the safety pamphlet about the aircraft, which was one of the types that had been grounded.

"I'm currently on one flying to @flySFO. A flight attendant was unaware of the emergency order. I still have couple hours left in my journey," he said on Twitter after he learned of the President's emergency order.

Other passengers were not too worried to be on one of the grounded types of planes.

Passenger Adam Crawford realized he was on a Max 8, flying from Tampa to Atlanta, when he, too, saw the safety pamphlet on the plane. He was on Southwest Airlines Flight 2531, which used a Max 8 plane, according to Flight Radar 24 and the FAA.

"It really didn't bother me," he told CNN on Wednesday. "I figured they would ground them if there was an issue. The flight was fine."

Some passengers never stepped on board

Dave Wasserman was waiting to board a flight at George Bush Intercontinental Airport in Houston when a United Airlines employee said the aircraft could not be used.

"Ladies and gentlemen, I'm sorry to say that we are not going to use this aircraft to go to Orlando," the employee announced in a video.

"As you know, there is some controversy going on about the 737 Max aircraft. This is a 737 Max 9 aircraft. The controversy is with the 737 Max 8 aircraft. However, there's been an order issued to ground this aircraft so therefore we are going to replace it with a different type of aircraft," she said.

Passenger Mort Greenberg was waiting at the gate in Miami on American Airlines Flight 2809 when the news broke that the government was grounding all Boeing Max 8 planes. He was scheduled to fly on a Max 8 plane, according to Flight Radar 24 and the FAA.

"Airport staff were upfront and said that was reason. Moments later, news came out about the President's order," Greenberg told CNN via Twitter.

The flight was canceled, according to American Airlines' website. Greenberg, who works in advertising sales, was supposed to be flying into LaGuardia.

American Airlines issued a statement about the Max 8 groundings.

"American Airlines has 24 aircraft affected by this directive," the airline said in a statement. "Our teams will make every effort to rebook customers as quickly as possible, and we apologize for any inconvenience."

Greenberg lauded American for communicating clearly and acting quickly to rebook his flight, he said.

"Better to be on the ground alive than falling to the ground and not being alive," Greenberg wrote.

Correction: The first section of this story has been updated to remove references that misidentified a passenger aboard Southwest Flight 1117 as being on a 737 Max 8. The plane was a Boeing 737-800, according to the FAA. A photo of a plane that was incorrectly identified as a Max 8 has also been removed.