You can find me in the air, on the water, on rails and on the road.
The general has led me into existence, and he also caused my demise.
I have created games, supported xenophobes and studied things both earthly and unearthly.
I have informed people in multiple ways, but also ended lives.
Who or what am I?
I have not always been around.
I am a tangible and defined object.
The games in the 3rd line refer to video games.
You mainly know me from my air implementation.
All the items on which the riddle is based can be found on my Wikipedia disambiguation page.
The xenophobes referred to in the riddle often make allusions to race purity. Their leader was seen as one of the biggest dictators of the 20th century.
Hint #7 (the last one)
The first letter of my name is also the last letter.