Busy airport,

Busy airport,
Passengers on a commercial airliner, waiting for the pilot to so they can get under way.
Finally... the pilot and copilot appear at the back(?) of the plane and make their way to the cockpit via the center aisle.
Both appear to be blind(?);
The pilot is using a white cane, bumping into passengers right and left as he stumbles down the aisle.
The copilot is using a guide dog.
Both have their eyes covered with very dark glasses.
At first, the passengers do not react thinking that it must be some sort of practical joke. (Is it April 1st?)
After a few minutes though, with the engines start revving, the airplane begins taxiing down the runway.
No explanation,... No punch line...
The passengers glance uneasily around.
They start whispering among themselves and look desperately to the stewardesses for reassurance.
Then the plane starts accelerating rapidly.
The people begin panicking.
Some passengers are praying.
As the plane gets closer and closer to the end of the runway, the voices are becoming more and more hysterical.
When the plane has less than twenty feet of runway left, there is a sudden change in pitch as everyone screams at once.
At the very last moment, the plane lifts off and is airborne.
Up in the cockpit, the copilot breathes a sigh of relief and tells the pilot:
"You know, one of these days the passengers aren't going to scream, and we aren't going to know when to take off!"