Two men who were supposed to fly on the doomed Ethiopian Airlines flight counting their blessings today. The pair said they missed the flight Sunday morning –– and one man called it his "lucky day" in a reflective social media post. The plane crashed and killed all 157 people onboard minutes after take off.

Antonis Mavropoulos, president of the International Solid Waste Association, said in a Facebook post with his boarding ticket that he was running late to catch Flight ET 302 bound for Nairobi. When he got to the gate, he saw the last group of passengers enter the tunnel heading into the Boeing 737-8 MAX aircraft, but flight attendants closed the door as he arrived.

"I was mad because nobody helped me to reach the gate on time," he wrote in Greek.

Mavropoulos was booked to the next flight that left a few hours later. But as he was about to board that flight, airport security took him in for questioning. He was initially upset, but one officer told him to "thank God" because he wasn't a passenger on the flight that was considered missing then.

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Later, he found out through a friend's text that the plane crashed minutes after takeoff from Addis Ababa airport. He realized if it wasn't for "two random circumstances," his fate would have been much different.

"The moment I made that thought I collapsed because then exactly I realized how lucky I stood," he said. "Really, it's the first time I'm so glad I wrote a post and I'm grateful to live and that I have so many friends that made me feel their love."

Mavropoulos told private Greek broadcaster Skai TV that he was traveling to Nairobi to attend a United Nations session that began on Monday. At least 19 people associated with the U.N. died in the crash. Both Addis Ababa and Nairobi are major hubs for humanitarian workers.

Another man, Ahmed Khalid, was traveling to the Kenyan capital to visit family members. He was coming in from the United Emirates when he missed his connecting flight in Addis Ababa because of a delay, according to Dubai-based newspaper The National.

"Everyone was asking the cabin crew what was happening, but no one was saying anything, Khalid told The National. "They were just going up and down until one of the passengers saw on his mobile that the first plane which had just flew, like six minutes after it flew, it just crashed."

For now, Ethiopian Airlines has temporarily grounded its fleet of Boeing 737 Max 8 planes. Other airline operators have followed suit since the same model operated by Lion Air crashed off Indonesia in October 2018.

Ethiopian Airlines confirmed in a tweet that both of the plane's "black boxes," the flight data and cockpit voice recorders, had been found as officials determine what caused the crash.