Well, why don't you reach up, pull some out and strike sparks into it with a firesteel or touch a match to it...and find out?
You will probably find that it is not especially flammable. But yes, hair can be used to help start a fire if you are doing a firebow and don't have anything to use for the string. If your hair happens to be long enough, it can be twisted into a fine, strong cordage like this:
Set mine on fire lighting gas wall stove one winter. Just flashed and hair sizzled.
Burned half a mustache off working for dry drilling outfit.
Captain Janeway used her hair to start fire on Voyager.
Haven't you seen funny tv videos where people's hair catch on fire at weddings/mass??