There is no confirmed evidence of airborne transmission of Ebola Sudan, Ebola Zaire, or Ebola Tai between humans. There have been no clinically proven cases of airborne transmission between monkeys; however there was a recent report in ProMED that two control monkeys caged across the room from monkeys infected with Ebola Zaire died of Ebola Zaire. It appears that the Ebola virus might have been spread to the control monkies by an aerosol produced by someone cleaning the infected monkeys cage with a hose. It is hypothesised that the Ebola virus became "airborne" by being caught inside small droplets of water that the control monkeys eventually breathed. Further study is needed to clarify this.
The Reston strain appears to have been transmittable by airborne means, but that particular strain is not known to be harmful to humans.