A group of professors were called and sat on a plane.
When the doors closed and the plane is about to take off, all the professors were informed that this plane is made by their students. All the professors rush toward the plane doors trying to escape, with exception of One professor who remained seated with confidence and calmness.
Someone asked him why he's not escaping the plane.
Professor answered "They are our students."
He was asked "Are you sure that you taught them well?"
Professor replied quietly: