These attempts are usually promptly halted by crew members.
See also: How to combat your fear of turbulence
But can plane doors actually be opened while the aircraft is thousands of feet up in the sky?
The short answer is that you'd have to be very strong to do it - so strong that it's basically impossible.
The inside of plane cabins are set to have much higher pressure than the air outside planes.
To open the door, one would need to overcome more than 24,000 pounds of pressure.
There are also lock bolts than hold the doors together, and permission from the cockpit is required to disable them.
Even if a passenger did manage to open a door, it doesn't necessarily mean it's time to panic - it could get loud, humid and foggy and then temperature might drop but it would not be dangerous.