They sued, of course.
And they've got a bit of money apparently, in a settlement with the airline:
The case of the flying imams who were removed in November 2006 from a USAirways flight in Minneapolis for questioning by law enforcement authorities concluded in the Minnesota federal district court before Judge Ann Montgomery. The parties arrived at a settlement of the case on October 20 in a court-supervised conference. The amounts paid by the defendants remain confidential.
So when our jihadi enemies use one of our airplanes as a weapon, and you wonder how they possibly could have done that after 9/11, recall this case.