The monkey facility in Reston where the virus was first noticed was not very clean. The monkeys that got sick in the second room in the facility could have been exposed through fomites.
That being said basically the entire book about ebola is being rewritten right now in West Africa. It is mutating and evolving. I'm guessing that it's only a matter of time before one become truly airborne. As it is a sneeze or being in the same room with someone is enough to get sick. The driver of a car that took one medical victim to the hospital got sick and died. That's just a matter of breathing the same air and/or touching something that the original victim touched. Ebola isn't hard to get at all.
This is consistent with droplet and/or fomite transmission. For Ebola to become truly airborne, it would have to evolve certain characteristics, and I do not know if it has that capability. You will not get Ebola by being on the other side of the room from someone sick with Ebola--although that is sufficient to catch airborne diseases.
It's for sure airborne. Read any account. They dissected the lungs of infected monkeys and saw that the lung material was infected with the "budding" virus...in other words, it was budding and releasing the virus into the airway.