Race for the Sky: The Kitty Hawk Diaries of Johnny Moore — Dan Gutman

Johnny Moore lives in Kill Devil Hills, North Carolina at the turn of the twentieth century. He is there to witness the Wright brothers make history by becoming the first people to fly. But Johnny's life changes years before the dramatic first flight, when his mama gives him a blank book and tells him to write in it.
At first, Johnny doesn't think he has anything interesting to write about in his journal. When he does put his pencil to the paper, his spelling and grammar are terrible. But pretty soon some "dingbatters" from Ohio, called the Wright brothers, breeze into town and Johnny starts to have more of a story to tell. Before he knows it, he is writing every day, telling about helping the Wrights build their flying machine.
Over the course of three years, he forms a friendship with the odd brothers from Ohio, improves his writing and grammar quite a bit, and if he waits long enough, he might even get to fly!