Alright, so according to Bernoulli's principle says that moving fluids result in a lower air pressure. Light and all electromagnetic waves are fastest in a vacuum. Lower air pressure is closer to a vacuum. So... Marginally? I have no idea how much but I'm guessing it's miniscule enough to need special equipment to detect. Not worth it. Plus the fan itself could block the waves. The fields around the wires powering the fans would have an effect as well. All of this is going to be super minor but I think the physical blockage of the fan is going to have more of an effect (but still teeny tiny) than anything.