Spaceships in science fiction, as was first noted by a commenter in the early days of this blog, always travel at the speed of plot. This observation is recurrent, including in comments on the previous post.
The title is a mashup of this principle with Teresa Nielsen Hayden's dictum that plot is a literary convention, while story is a force of nature.
All of which goes to explain why this blog is, in some respects, a futile effort. When story collides with other considerations (such as realistic space travel), story invariably wins.
I have first-hand experience of this problem, which I will be delving into further in upcoming posts. Suffice it for now to say that when a cool technology led me to a story, the story took over completely. And I mean completely. Among other things, not one but two battle sequences ended up on the cutting room floor. They had become distractions from the story; therefore they had to go.
There are, at best, some limited protective measures. The most obvious is to go with the flow. If your story calls for fighter jocks, you are going to need fighters for them to fly. These don't necessarily have to be space fighters - if a planetary atmosphere is handy, air fighters are legit - but you will certainly need fighters of some sort.
The implausibility of space fighters won't get you off that hook. You'll have to either make them plausible - or else say the hell with it and go with implausible ones. This is an eminently safe option. The great majority of readers will neither know nor care. Of the relatively few who do care, most will forgive you. Especially if they like the story.
Other options are available. A radical but straightforward one is to avoid telling a story. This is the strategy I have followed in this blog. I've posted only a handful of fiction snippets here, and most of those had nothing to do with space. (My only actual rocketpunk SF has been a couple of paragraphs in a very early post.)
There is a modest but real interest in 'nonfiction' space speculation. It is not too hard to find blogs or other websites that discuss and describe imaginary spacecraft without trying to tell stories in which they figure. But such is the power of story that it is always lurking, waiting for a chance to intrude. To identify your laser star or killer bus as belonging to the Zorgon Empire is to invite speculation about where or what Zorgon is and how it became an empire. Warning lights flash and sirens warble, because you are now under intrusion by an incipient story.
I ought to note here that all of this applies not just to the details of spaceships and the like, but to the entire setting. I have mentioned a few times here that there are plausible space futures that are simply not very story-conducive. But the comment threads for those posts always veer toward how to get a story out of it.
Last post I mentioned that there are no known cases of spacecraft docking maneuvers being filmed from a third spacecraft. There turns out to be an almost-exception: The image of the Shuttle Endeavor - on its final mission - docked up to the ISS comes was filmed from a nearby Soyuz. It comes from this rather interesting blog.