In order for a plane to take off, it must suck in enough air through it's propellers if you will to get you off of the ground. Since a plane would NEVER spin around like a helicopter as it free falls, if it were to stop in midflight, it should go straight down. The propellers would not be able to get the steady take off in mid-air as it falls, thus making it impossible to stop. A plane has to constantly suck in air through the huge jet propellers to keep it in the air.