He said emotions spilled over from the moment passengers got to the tarmac to board the plane.
"It really caught us I think, to be standing on the runway looking up at this American Airlines 757. You just get a sense of how huge this thing is and how powerful it must have been and what a terrible thing occurred.
Another image that sticks in his mind -- American flags hung by the flight crew to greet passengers as they got on the plane.
"You saw people who got on the plane who kissed their hand and touched the flag, kissed the flag, but there were emotions that people had never felt I think.
Portman says even ground crews were moved by it all.
"I saw a flight agent from San Jose and another one of the ground personnel just stand there with their arms around each other and watch the planes taxi away," he said.
Portman said he also will not forget the moment when the pilot announced they would have military escort into the United States.
"It doesn't take a rocket scientist to figure out that the escort wasn't to keep the planes safe from threat, but to make sure the planes stayed on course," he said.
Portman said he has a mental picture of pure patriotism from when the pilot announced they were in U.S. airspace and applause rang out in the cabin and then again as they touched down in Dallas where they taxied past airline hangars.
"I saw the biggest American flag you've ever seen hanging from Delta Airlines and saw another hangar with American with a huge flag. You realized something had changed," he said.
"Some of the things that we've taken for granted have been moved to the forefront in terms of recognizing our country is important," he said. "The things we take for granted are important and unfortunately, it took something like this for us to realize that."
Portman also recounted another story that the flight crew shared with the other passengers. At the hotel where all of the flight crews and some American Military personnel stayed, Costa Rican employees held a candlelight ceremony and sang God Bless America to them.
Portman said there was not a dry eye on the flight.