You need to speak to the airlines directly, there is no magic back door. Be prepared for a rough ride though, as people are queuing at the doors for unpaid internships to gain hands-on experience. Contrary to what some folk think the airlines don't want unpaid hands in the hangars, since every trainee needs to be supervised by an experienced man which takes him away from what he could otherwise be doing.
Good luck anyway. Try approaching local flying clubs as a possible foot in the door.