Ahmed Mohamed Nasser al Soofi of Detroit and Hezam al Murisi were arrested on Monday after U.S. authorities found suspicious items in their checked luggage.
Al Soofi was stopped at a Birmingham, Ala., airport for additional screening because of what officials said was his "bulky clothing." Officials said al Soofi was found to be carrying $7,000 in cash and a check of his luggage found a cell phone taped to a Pepto-Bismol bottle, three cell phones taped together and several watches taped together. Box-cutters and knives were also found.
However, no explosives were found, so he was cleared to go onto Chicago O'Hare.
Once in Chicago, officials said al Soofi met Hezam al Murisi, and the two got on a United Airlines flight Sunday night from Chicago to Amsterdam despite security concerns.
Authorities said both men had checked luggage on a flight to Washington, D.C., but never boarded the plane.
When the flight landed in Amsterdam, they were detained by Dutch authorities at the request of American authorities.
A U.S. official said on Tuesday the two men did not know each other and were not traveling together.
The official, speaking on condition of anonymity to discuss the ongoing investigation, says both men missed flights to Dulles International Airport from Chicago, and United Airlines then booked them on the same flight to Amsterdam. The men were sitting near each other on the flight.
The Associated Press contributed to this story.