HOUSTON -- A bride and groom headed to Costa Rica for their wedding Saturday got kicked off a United flight out of Houston following an issue with seating on the plane.

Michael Hohl, the groom, said he and his fiancé, Amber Maxwell, were the last to board United Airlines Flight 1737 which was headed from Houston to Liberia, Costa Rica. According to Hohl, they noticed a man was spread across their row napping when they approached their seats, so they decided to move three rows up to row 21.

He said they didn't think it would matter because the flight was half full with multiple empty rows.

“We thought not a big deal, it’s not like we are trying to jump up into a first-class seat," said Hohl.“We were simply in an economy row a few rows above our economy seat.”

In a Boeing 737-800 like the one the couple was on, United considers Row 21 "economy plus," which is an upgrade.

After sitting, Hohl said a flight attendant approached and asked if they were in their ticketed seats. The couple explained they weren't and asked if they could get an upgrade, but instead they were told they needed to return to their assigned seats.

Hohl said after complying with the flight attendant's demand, a U.S. Marshall came onto the plane and asked them to get off.

The couple cooperated and got off the plane without incident, but they still don't understand why.

"They said that we were being disorderly and a hazard to the rest of the flight, to the safety of the other customers," said Hohl.

United Airlines said in a statement that the couple tried to sit in an upgraded seat "repeatedly" and they "wouldn't follow crew instructions."

"We’re disappointed anytime a customer has an experience that doesn’t measure up to their expectations,

the airline said in a statement. "These passengers repeatedly attempted to sit in upgraded seating which they did not purchase and they would not follow crew instructions to return to their assigned seats. We’ve been in touch with them and have rebooked them on flights tomorrow."

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