Ebola is made of RNA. RNA viruses are known to undergo rapid genetic changes. The three most common mechanisms are:
- Nucleotide substitutions resulting from purportedly high error rates during RNA synthesis;
- Reassortment of the RNA segments of multipartite genomic viruses
- RNA-RNA recombination between non-segmented RNAs
The Ebola virus can use only the first and the third mechanisms as it has only one segment of RNA by capsid. To become "airborne", the Ebola genome (RNA) would, at least, have to mutate in such a way that its outer protective coating of proteins (capsid) could resist the forces to which they are subjected in air (e.g., dryness). It also would probably need to change structure to allow infection through the respiratory system. There are no exact measures of the rate of mutation in Ebola, but the probability of the required mutation(s) happening is not great.