The metal used for making aircrafts and rockets is

Aluminium is the metal commonly used for making aircraft and rockets due to its advantageous properties. Aluminium is lightweight, which is crucial for aircraft and rocket construction to reduce fuel consumption and increase payload capacity. Additionally, aluminium has good corrosion resistance, which is important for structures exposed to harsh environmental conditions, such as those encountered during flight. Lead, nickel, and copper are not typically used for making aircraft and rockets due to factors such as weight, strength, and corrosion resistance.

Option A: Lead is not suitable for aircraft and rocket construction due to its high density and poor strength-to-weight ratio.
Option B: Aluminium is the correct choice, as explained above.
Option C: Nickel is not commonly used for aircraft and rocket construction. While nickel may be used in certain aerospace applications, it is not the primary metal used for aircraft and rockets.
Option D: Copper is also not typically used for making aircraft and rockets due to its high density and poor strength-to-weight ratio compared to aluminium.