[ThrustVectoring]

Evolution does not work that way. Parasites are generally happy to keep on reproducing until their host dies - there's no reason for them to stop, since the only reasoning that evolution understands is "there tends to be more things that reproduce better". Malaria reproduces better by going through human hosts and mosquito carriers than by going airborne. If going airborne helped an individual generation of malaria, malaria would already be airborne.