Neither Trump nor his new policies had anything to do with the downward trend in aviation accident fatalities. But if he wants to take credit, eh, so what? Good that he is insisting on strictly enforcing the FAR's (Federal Aviation Regulations).
He better be careful, though. I've worked in the industry for more than 30 years and I promise you there will be deaths from mishaps in the future. Will he still want to take credit then?? If he really wants to affect real, sustained improvements he should look at reforming the FAA which has become nothing more than a Federal jobs program for the marginal players in the industry.
Just like there will be a time when the stock market will decline.