Tayammum on Different Surfaces and in an Airplane

Tayammum is valid with every pure substance that is from the category of earth, such as soil, sand, stone, pebbles, bricks, lime, or a wall that has dust on it.

principle :

Anything that melts or becomes soft when exposed to fire is not valid for tayammum, such as gold, silver, iron, copper, glass, plastic, cloth, wood, oil paint, and similar materials.

And anything that does not melt or soften in fire, but remains in its original form, is valid for tayammum because it is considered from the category of earth.

Therefore, tayammum on cloth, plastic, iron, or walls coated with oil paint is not valid if there is no dust on them. However, if such a wall or object has enough dust that comes onto the hands, then tayammum on that dust is permissible.

In an airplane, 

if using water is not possible, or there is fear of harm or illness from using it, then tayammum may be performed by striking the hands on clean dust present on the seat, window, wall, or any similar surface.

The method of tayammum is:

Make the intention of tayammum, strike both hands on the dusty surface, then wipe the entire face. Strike the hands again and wipe both arms including the elbows. This is the correct Islamic method of tayammum.