The helicopter ride

Bill and his wife Blanche went to the air show every year and every year Bill would say: “Blanche, I’d like to ride in that helicopter.”
Blanche always replied: “I know Bill, but that helicopter ride is £50 and £50 is £50.”
One year Bill said: “Blanche, I’m 75, if I don’t ride in it now, I might never get another chance.”
The pilot overheard the couple and said: “Look, I’ll do you a deal. If you can stay quiet for the entire ride, I won’t charge you a penny.”
Bill and Blanche agreed and up they went. The pilot did all kinds of fancy manoeuvres but not a word was heard.
When they landed, the pilot turned to Bill and said: “I did everything I could to get you to shout out, but you didn’t. I’m very impressed.”
Bill replied: “Well, to tell you the truth, I almost said something when Blanche fell out, but, you know, £50 is £50!”