Airborne transmission makes measles vastly more infectious than Ebola.

Evidence

Its calculation depends on at least three main factors: the infectious period (how long an infectious person remains contagious); the mode of transmission (how the virus spreads, for example, airborne versus physical contact); and the contact rate (or how many infected people a person is expected to come into contact with). For example, although Ebola is deadly, it spreads primarily via bodily fluids, whereas measles is much more infectious because it’s airborne and can spread via droplets. Measles’s Ro is estimated to be between 12 and 18 – one of the highest reproduction numbers on record. — Sander van der Linden, Foolproof, 340