When you are in aeroplane and the clouds are very low, the pilot might make an emergency landing.
When you are in an airplane and the clouds are very low, the pilot might fly above the clouds or make an emergency landing.
When you are in an aeroplane and the clouds are hanging low the visibility of the plane will be poor, therefore the pilot might decide to make an emergency landing or fly above the clouds.
What happens when the clouds hang very low is that it becomes foggy. Fog is clouds that are very low to the ground and that are are made up of tiny water drops.
When the clouds are hanging really really low, there will be poor visibility especially if you are flying an aircraft.
Fog and low clouds
The lowest clouds are called fog. The classification of low clouds is stratiform.
Because those trails are clouds. The airplane's wing sheds low pressure vortexes from their tips, the low pressure encourages condensation of water vapor to form the small droplets of water that make up clouds. The airplane's jet engines emit lots of water vapor in their exhaust. Often at the very cold temperatures where these airplanes fly (above 30,000 feet) the water droplets in these clouds freeze, becoming ice and making the clouds last much longer.
middle clouds
high clouds means there will be good weather and low clouds mean stormy weather
It is the rising air in the center of the low that causes clouds and precipitation (not necessarily warmth though.
low clouds
Stratus clouds