Airplanes aren’t stationary!
But they appear so if they are coming straight at you.
Nonsense. You can make an airplane out of stationery.
Our back pasture is on a nearby airport landing glide path. Sometimes a landing plane coming straight at you can appear stationary for a bit of time. Have even seen them turn landing light on and off during approach, which will get your attention.
Opinion on original question, I suspect it was a satellite reflection. Depending on its position in relation to western horizon sunlight obstructing landmarks. It would be far out to see a star go Nova, but as another poster noted that takes place over several days, not seconds.