I had to ask this, I've never heard a believable reason why a craft from the far ends of the Galaxy or further from the Universe or alternate dimensions NEED external lights? The only one I ever heard that remotely made sense was to help Earthly aircraft from coliding with them - but that seems a bit of a stretch.
If they really wanted to stay invisible, wouldn't they simply turn them off in the night sky so they didn't grab our attention in the first place and adversely, if they wanted to be seen wouldn't they make more of a statement than just cruising overhead with their running-lights on - lol.
If they are just doing it to tease us, isn't that a bit immature for supposed advanced civilazations?
I tend to think that they may not be advanced, they just have a nitch over us in being near wormholes or other galactic teleporters which know nothing about. I tend to think their ships otherwise are similar to ours. They can hover, we can hover (harriers, helecopters) they have stealth (we have stealth - at least from radar) they can move fast and so can we.
The incidentals may be different, the limits of their ships may be different then ours, but still they seem to have limits.
All these craft styles, triangle, oblong, round could easily be from the same civilization, we have craft of many different shapes, sizes and purposes too!
Seriously, I think the real edge they may have is location location location - otherwise, I don't think we are all that far from similar technology.
So... Why do space craft have running lights?