Make sure you have the infrastructure in place to do the recruitment to start with. Recruit cadets without it, then you’ll give them a poor experience and they won’t be retained (and that recruitment effort and training is wasted) - or worse, with leave and share their negative experiences with others.
I’d start looking with steady, sustainable growth rather than high impact mass recruitment activities. It gives a better, long term future for the squadron.
Personally, I’m a huge fan of recruit intakes. But we keep them relatively small - 8 cadets per intake. They then travel through their cadet life together. We also run a waiting list - don’t be afraid of doing this. If you get an inquiry, do invite parents/potential cadets down for the evening for a tour - but make sure you have the capacity to impress them on that evening - then they won’t mind a 2 month wait until the next intake session. Keep them engaged whilst waiting with positive communications.
Work with the communities around you. Schools, parish/town/village councils. Local RBL or armed forces charities. Get yourself out to community events. Work with Commonwealth War graves and your local churches to do some maintenance/restoration activities. Get the squadron known as a reliable, helpful and switched on you group through the community channels - build it to be the youth club or choice by reputation - that REALLY helps with engagement.
Utilise social media - but know and target audiences appropriately. Future cadets won’t be using Facebook - but their parents/grand parents will. Use cadets themselves as your ambassadors - get them to tell their stories. There will be loads of things that you’re doing which can be used to showcase the squadron, and champion your successes - promotions, progressive training badges, “cadet goes gliding”, weekend camps, AT, DofE success, “cadet secures place on prestigious camp”, “cadets get up close with RAF at RIAT” etc.
Use schools - but not necessarily for assemblies exclusively and in isolation. Instead, invite down the Head of Year 8 or 9, Pastoral Managers or Careers Leaders for your local secondary schools (details will be on the school websites) - give them a tour and showcase your squadron; they can be an excellent conduit to getting young people engaged in positive activities outside of school too.
Get yourself listed in local directories. Your Council’s “local offer”, any “what’s on” type magazines, Parish newsletters etc. they are largely free, but another way to get the message out there.
You could also try exploiting your alumni network (if you have one! If you haven’t, start building one with an Open Day for ex-cadets and get the word out (it makes for a really good PR activity anyway). Reengage them as potential ambassadors, use their stories (if they are willing to share!) to help reinforce the good stuff your squadron does, but also as an extension of the squadron - see if they’d be willing to rejoin the CivCom or - even better - potential staff! BUT they will also be able to spread the good word and get the squadron name out.