#santa-sleigh {
  position: fixed;
  top: 15%;
  left: -400px;
  z-index: 9998;
  pointer-events: none;
  animation: santaFly 25s linear infinite;
}

#santa-sleigh img {
  width: 300px;
  max-width: 40vw;
}

@keyframes santaFly {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(calc(100vw + 500px));
  }
}