Cabin Crew Reveals What Really Happens When Flying

Why do planes leave white lines in the sky?

The white lines that planes emit when traveling across the sky are called condensation trails, or contrails. Contrails occur when the plane's hot vapor meets the cool air in the atmosphere—similar to how we can see our breath in winter.

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The More You Know

  • In 1966 and 1967, soldiers testing Agent Orange in Canada were told the chemical was completely safe and sprayed it on each other to cool off.
  • The tongue is the only muscle in the body attached from one end.
  • The speed of a computer mouse is measured in "Mickeys."
  • In 1923, jockey Frank Hayes won a race at Belmont Park in New York despite being dead — he suffered a heart attack mid-race but his body stayed in the saddle until his horse crossed the line for a 20–1 outsider victory.
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