Over the years, terrorists have used sports drinks, shoes, and even underwear to hide explosive material. Now, authorities in Spain say three terror suspects were experimenting with ultralight planes.

Spanish authorities believe the terrorist intended to use pleasure craft for far deadlier purposes. They also believe they were linked with al Qaeda, long known for its obsession with arming aircraft.
    
Today a judge in Spain's National Court will question the suspects and decide whether they'll remain detained. They include a Russian, a Russian of Chechen descent, and a Turk.   

Authorities arrested the Turk in the southern town of La Linea and picked up the other two in the central town of Ciudad Real.

"I can confirm there are clear signs that these people could be planning a terrorist attack in Spain and/or other European countries, and that the three of them belong to al Qaeda," Spanish Interior Minister Jorge Fernandez Diaz said.

He said that explosive material found in the Turk's house in La Linea could "destroy a whole bus."

Authorities say two of the suspects had practiced flying in light aircraft and another is an expert in explosives and poisonous substances.

Diaz said the sting operation involved close collaboration with intelligence services from "Spain's allies." He added that Spanish authorities had been watching the three for some time.

Spanish police arrested dozens of al-Qaeda suspects after 9/11 and more after the 2004 train bombings in Madrid. Those bombings killed 190  people and wounded 1,800 others.