There is no restriction on travel in this case. It is simply that by revoking Wilson's passport, the US government has presumably worked behind-the-scenes to assure that Wilson, as he lacks a valid passport, will be deported or otherwise ordered out of the country and returned to his last origin, e.g. the US. On arrival in the US, he will presumably be arrested by appropriate law enforcement officials and ultimately returned to the court issuing the warrant for further proceedings.