Oh this is so easy.
Show a picture of a dork. Lonely , unhappy, longing for company.
Show a picture of a suave, james bond type. With lots of babes in bikinis next to him.
IN THE BACKGROUND, YOU SHOW A VERY NICE GENERAL AVIATION AIRPLANE ( I think a piper saratoga, maybe with the rear seats removed and a mattress in place).
Having a PPL means you can fly a plane and impress the girls.
Not having a PPL means you can't fly a plane and are a dork.
There you go. SEX. It sells.
NOW I realize the ppl in europe is a bit more restrictive than in the USA. But in reality, all a PPL does is let you continue learning how to fly better.