Without having the information about what the options are there really is not any way to know which is lighter than aircraft. The rest of the information needs to be provided for the correct answer to be given.
Yes, ozone is lighter than air.
Ammonia is lighter than air. It has a lower density than air, so it can rise and disperse in the atmosphere.
Anhydrous ammonia is lighter than air, with a specific gravity of 0.597 compared to air. This means that it will tend to rise and disperse in the air if accidentally released.
Magnesium is denser than air, so it will sink in air rather than float.
Yes, propane is lighter than air. It has a density of approximately 1.88 kg/m³ (0.1179 lb/ft³) which is lighter than the density of air, which is about 1.225 kg/m³ (0.0765 lb/ft³). This is why propane tends to rise and disperse in the atmosphere.
aeronaut
There are "lighter-than-air" craft which are known as blimps or balloons, "heavier-than-air" craft which are divided into fixed-wing (airplanes) and rotary wings (helicopters).
There are two types of air-craft: Heavier-than-air and lighter-than-air. Lighter-than-air craft are things like zepplins and balloons that, due to the gas inside actually weigh less than air, and so float upwards. Heavier-than-air craft are basically everything else. Airplanes and the like are not able to float on air and require some sort of thrust and lift system to get them airborn.
Balloons, dirigibles and zeppelins are lighter than air aircraft. Gliders may count as well but I am not positive.
"Lighter than air" aircraft are lighter than air! The most common are blimps. They do not rely on wings to generate lift. They contain a lighter than air gas (ex:helium) that lifts the craft into the air when ties to the ground are released. "Heavier than air" aircraft are the opposite. They rely on wings to generate lift to get into the air. Common heavier than air aircraft are general airplanes you see in the sky everyday.
Dirigibles are lighter-than-air aircraft that can be maneuvered by their own power. There are different kinds of dirigibles, such as blimps and airships, but all are distinguished from other lighter-than-air craft, such as balloons, which do not have their own steering and power sources.
An airplane is a heavier than air flying craft
An airplane is a heavier than air flying craft
Yes, ozone is lighter than air.
HYDROGN IS 14 TIMES LIGHTER THAN AIR.
No, by the time WW1 rolled around, the term was out dated.
100% of hydrogen is lighter than air