user: What is the best way to earn money on the side?

assistant: Sell your unused belongings.
Buy, refurbish and then sell other peoples' belongings for a profit.
Tutor primary school students as the curriculum should be fairly straightforward and the main value-add is being present to guide children on school subjects or on homework.
Turn your hobby into a business.
Start your own website or blog and earn money through selling advertising on your website or blog.
If you are a dog owner, start a dog walking business.

user: Are there companies that build a plane end to end?

assistant: A plane is typically not created by a single entity, but instead is a collaboration between numerous parts manufacturers and assemblers.

user: Who invented the telephone?

assistant: In 1876, Alexander Graham Bell was the first to obtain a United States patent for a device that produced a clearly intelligible replica of the human voice on a second device.
A resolution passed by the United States House of Representatives on June 11, 2002 called for recognition of Antonio Meucci's work and contributions towards the invention of the telephone.