Investigators say 18-year-old Dallin Morgan and a 16-year old boy planned to get away by stealing a plane from the Ogden Hinckley Airport, about 35 miles outside Salt Lake City.
Morgan and the 16-year-old were pulled out of Roy High School Wednesday after authorities learned of the plot. They were held for hours of questioning and arrested.
A sweep of their high school, as well as the suspects' homes and cars, turned up no explosives.
Police say the suspects prepared for the attack by logging hundreds of hours on flight simulator software on their home computers.
Morgan was held on $10,000 bail at Weber County jail on suspicion of conspiracy to commit mass destruction. The juvenile was in custody at Weber Valley Detention Center on the same charge. Prosecutors are weighing possible additional charges.
The Associated Press contributed to this report.
