Writing a fictional account of an actual event
I have just completed a novel that begins (several chapters) with one of the most famous UFO sightings. The incident took place in 1950 and the two real life people involved died in the late 1990s. I don't disparage or criticize their characters. In fact, I come down in support of their claim that they saw and photographed a real object. It was not a hoax. I adhere to the well known (in ufology circles) facts of their story, which are readily researchable online, although I have fictional scenes to explain how decisions were made. The characters are not the lead characters of the novel, but their story is the jumping off point that sets things in motion. I am reluctant to change their names or circumstances because this case is so well known. There is a celebration of the event held every year in Oregon, second only in popularity to the annual UFO event held in Roswell.
In another section of the book, I deal with a lesser known case about a pilot who disappeared in the early 1950s while chasing a UFO. The Air Force investigation said he likely crashed, but his plane was never found. In the novel, I have him being found by the protagonist in a mental hospital, where he has been since the 1980s. Funny thing is when he showed up at the hospital thirty years after he was supposed to have died, he had not aged a day. The protagonist interviews him as to what happened to
him. The character is not criticized or disparaged. Other than being in the hospital, which he refuses to leave, he seems rather normal. I utilize his biography and the report of the Air Force investigation to flesh out the interviews. While it is not critical that I keep his real name, it is a case well known to many of the likely readers. Using his real name would add authenticity and realism.
Basic question, what concerns should I be award of?
Answer: As always, I am not a lawyer and cannot give legal advice.
That said, I don't see any serious areas for concern.
On the one hand, to many people the whole UFO field is fiction, so if you want to write novel in which aspects of it turn out to be true, that's perfectly fine. Lots of other writers have done similar things (Whitley Strieber for one).
It sounds like you are paying respect to the historical facts, so no one can say you are slandering anyone, especially as your main characters are fictional. Writers have a fair amount of leeway in depicting historical figures.
Where you might consider fictionalizing a historical character (i.e. replacing him with a character who is very similar but with a different name and some details changed) is if the character is presented in a way that is controversial. But from your brief description, I don't see an issue.
Of course, a publisher might have other thoughts, but I wouldn't let that possibility hold you back.
Best of luck,