In these modern times I am astonished that none of the (admittedly not many) clubs I have frequented have any kind of email system set up so that interest can be maintained.
I think if I ran a club I would take the email address of every single person that set foot in the club and make sure that from then on they were aware of every event, special deal, fly out, discount, change of rules or whatever was on offer.
EG: I attended an excellent aerobatic beginners day last year. It was very well run and all participants were later emailed with their results, but there's been absolutely no follow up.
Whereas last week I bought a switch for six quid and today I got an email from the company asking if everything was OK. Good service.
Some enthusiastic individuals do attempt it off their own back but it's not the same as coming from the club itself.
Too many clubs leave the initiative to the member/visitor/individual employee.