What is hidden in 3D image?

A beautiful young model boarded a plane to New York with a ticket for the economy section. She looked at the seats in economy, and then looked into the forward cabin at the luxurious first-class seats.
Seeing that the first-class seats appeared to be much larger and more comfortable, she moved forward to the last empty seat in first-class.
The flight attendant checked her ticket and told the woman that her seat was in economy.
The blonde replied, 'I'm a famous model, and I’ve never had this problem before. I'm going to sit here all the way, until we get to New York.'
Flustered, the flight attendant went to the cockpit and informed the captain of the problem. The captain went back and told the woman that her assigned seat was in economy.
Again, the blonde replied: 'I'm a famous model. I'm sitting here all the way to New York.”
The captain didn’t want to cause a commotion, and so returned to the cockpit to discuss the blonde problem with the co-pilot.
The co-pilot said that he used to date a model like her, and that he could take care of the problem. He then went back and briefly whispered something in the blonde's ear.
She immediately got up and said, 'okay, thank you'. She then hugged the co-pilot, and rushed back to her seat in the economy section.
The pilot and flight attendant, who were watching with rapt attention, asked the Co-pilot what he had said to the woman.
He replied, 'I just told her that the first-class seats aren't going to New York.'