From my eye view, one of the most important invention is plane, for the reason that we are able to go anywhere as fast as we want.
To starts, airplane changed the humanity future and got better the transportation system, at the beggining the tickets were too expensive just wealthy could get it, nowdays everybody can buy a fly ticket. Indeed you can chose a tourist, bussines class or fist class, the above allows reasonables prices.
Another fact I would like to mencion is about time, it is a treasure so how much time the plane saves us and is the most safe transportation. The last time I flyed when I went to Tijuana it was about 3 hours it is one of the longest trip I ever got.
To sumarize I cannot imagine my life without airplane, I am an environmental advisor so I often travel, may I say airplane make my life confortable and easy otherwise I must to go by bus.
Besides the airplane It is the basis of aeronautics and has promoted space ships and with this a further step of humanity is that the man walked on the moon and now we are exploring other planets.