A bit misleading there PN, or perhaps just over zealous in trying to get someone sign up
Being an Airman would not give you a much greater chance of 'becoming' NCA - surely the stats show that by far the majority of NCA join directly from civvy street. Once you are in, you have the additional challenge of having to amortise some training and having to get out of the trade you are in - both of which may make the transition quite tricky.
The only reason to join up first would be if you needed to make use of any flex in the age limits between direct entrants and serving airmen, even then it would be pretty tight - Anyone know any airmen that have transferred to NCA within 4 years of joining up?