Concept:
A hangar is a building used for parking, servicing and maintenance of aircraft.
The dimensions of a hangar depend primarily on the physical dimensions of the aircraft that it is intended to accommodate.
These dimensions include:
• Aircraft length.
• Wingspan.
• Overall height.
Step 1: Understand hangar planning.
Adequate clearance should be provided around the aircraft for maintenance operations.
Hence, the hangar dimensions are governed by the aircraft dimensions.
Step 2: Identify the correct option.
Therefore,
\[
\boxed{\text{Hangar size depends on the length, wingspan and height of the aircraft}.}
\]
Hence, the correct option is
\[
\boxed{(D)\;\text{The length, wingspan and height of aircraft}.}
\]