The first report that I saw on this situation made these men look very innocent. However, there must have been a very good reason that the pilot refused to fly with these particular imams on board his flight.
The first incident involving these men happened a few years ago. At that time they were returning from a conference, and they began to behave suspiciously to the point that passengers were afraid to fly with them. On that first occasion these imams used a variety of intimidation tactics to spook the passengers.
Big Peace has a very good background article on the whole saga. It details their backgrounds, including their links to radical Muslim groups, including links to Al Qaeda and Osama Bin Laden. I assume that something happened on board the flight that caused the pilot to be spooked about them being on board. Maybe he recognized their names.
Either way, these men are playing a very deceptive game, one that has been coordinated with CAIR. The death of OBL seems to have given them a new impetus to attempt their intimidatory tactics against American travelers. Rather than giving them access to the courts they should be thrown out of the country because of their undesirable behaviour.