Sign up

It is extremely unlikely for a frequent flyer to not sign up for an airline loyalty program. This act would be a stupid extravagancy. Long lines, exhausting procedures, lose of time and money. Thus as an airline company, your invitation is not vital maybe not necessary. You invite or not they will sign up.

Calling for "Follow us on Social Media" tho is very hard to sell. They will not pay attention. They will not engage. Because engaging with people with no obvious benefit or satisfaction is vastly rigid. Next time when you ask them to join you in those fancy billboards ask yourself first: “Why they should do that?“.