Air inc seminars are various companiies doing an overview of their hiring etc., Air inc briefings re the industry and who is hiring (with what experience), then there is a meet and greet time where you stand in line to meet the recruiters from the airlines who are there that interest you. Basically you stand inline for up to 30 minutes and then chat with the people from the airline for 5 minutes or so.
If you do it realize that you have 5 minutes to sell yourself and leave a GOOD impression. Think of it as a mini interview and prepare accordingly.
CX wasn't going to the job fairs back when I went, but it is probably worth doing. The job fairs are also pretty good as they get you in the right positive mood to be looking for a job.