But I don’t see “fall” as having any direct effect on my understanding.
E.g., if someone asks about “Jack fell down the hill.” and I don’t mention Jack, I don’t think I’ve seriously missed anything.
Exactly–not not mention affect. To view language use as though it were an assembly line of information transfer that should achieve some kind of efficiency ratio is to willfully ignore its full breadth and purpose.
Your understanding is one thing, but the OP is asking which adverbial phrase to use with fall
It’s a question of usage–which of the two adverbial phrases is customary. Such customs–or collocations–are often purely idiomatic, but they’re still governed by the constituent parts. So, for example, you can’t say whether it’s more customary to say out of memory or from memory unless you know the whole phrase. The computer is out of memory. vs.
I know the whole song from memory.
Maybe, but we’re not talking about the subject of the verb here. Few people would say, for example, ****Jack fell around the hill.******Fall ***doesn’t collocate with around, in this particular case, so it’s necessary to stipulate that the verb in question is fall if you want to know whether to use down or around.
I guess the OP is trying to find words to convey that the bird’s normal course is interrupted in mid-flight, and it is not descending by design. Still, why this obscure distinction (about this particular event) would have been bothering the OP “forever” strikes me as odd.
Proposed improvements:
“The bird fell in mid-flight”
“The bird was flying and suddenly fell”
Proposed ridiculous versions:
“The bird was flying, and then, out of the blue, it fell”
“The bird was flying, and then out of the blue it fell” 
You can think of no context where this is a perfectly cogent sentence? Now that’s ridiculous.
Ditto. Think of Icarus. The repeating of where birds fly is reinforced with a lovely sensual synecdoche as well as a double entendre. It’s nice.
No, I know it’s cogent, just its pun quotient is a bit high for everyday use.
Has it been bothering you for ever or forever?
Often, it is not a matter of “grammatically correct”, it is a matter of what sounds smooth or even elegant in speech or writing. I believe that your hypothetical case is an example of the latter.
Okay, but what is it exactly that makes something not sound “smooth or elegant”? It isn’t a mystical, unknowable thing, but rather, it usually is a question of collective usage patterns, which can be shown with corpus data.
Probably the most useless comment that traditional writing teachers make in the margins of papers of developing writers is the single word “awkward.” That awkwardness is only apparent to someone who has extensive exposure to written (academic) discourse, which is obviously not the situation for a developing writer, no matter who it may be. (It’s not because of “kids these days” or “deteriorating standards.”) It’s simply the normal, inevitable process of becoming socialized to academic discourse, which everyone must go through, and it will always be that way, for everyone. Some may have more exposure, earlier or at a higher rate than others, but they still must go through it.
The term “awkward” is meaningless to someone who hasn’t yet had that exposure, and it doesn’t help the developing writer, but so many unthinking writing teachers don’t realize that, because it has been so long since they themselves were developing writers. They just assume that this sense of “awkwardness” is some kind of inborn or natural awareness, but it’s not. It’s the outcome of extensive, collective usage, that takes time to absorb.
It’s not a “useless comment” if you, as a student, follow up on it and get some one-on-one input from your instructor regarding what you could have done better.
Great writers, like great musicians or artists, are a combination of hard work and a natural gift. Part of that hard work is following up on constructive criticism and doing the things necessary to improve weaknesses.
A large working vocabulary coupled with a deep knowledge of correct language usage are essential building blocks in the process of becoming an effective writer.
Well then the instructor should just give that input in the first place.
We all know that such feedback is intensive and time-consuming, and so many instructors hope they can get away with just writing “awkward,” and that the student will magically see what to change.
The research on the long-term effectiveness of feedback in writing instruction–including that which addresses these points of “style”–repeatedly shows that such feedback needs to be negotiated with the student, and grounded in the content of writing, which means it requires a major time commitment that usually isn’t available to most teachers.
guizot, your response is to look at the data of collective usage and show the phrasings are both uncommon. But that does nothing to explain why they are uncommon. People attempting to explain their own choice and why are attempting to answer the part of the question you are missing.
Your example was “The bird fell.” It said nothing about flying. The OP’s example was discussing flying, but your example was without context.
What seems more important is why the bird fell, and was it a fluttering attempt to retain flight or a limp drop like the bird was dead, etc.
This example makes no sense. In that sentence, Jack is the subject, so leaving Jack out does affect the meaning conveyed by the sentence. Furthermore, fall was the word you were trying to indicate is not significant, except in your example, fall is the key action - leaving it out changes how Jack got to the bottom of the hill.
To your point, while the OP did ask specifically about a bird and that bird falling and then which phrase [from midair, out of midair) fit better, I agree it is not wrong to skip the bird part and the falling part when trying to digest “from midair” vs “out of midair”.
Besides, to me, I would probably emphasize more the directness and the cause of the fall.
The bird suddenly fell from midair.
The bird suddenly fell out of midair.
“From midair” reads better to me. I think Riemann does a great job explaining why “out of midair” is awkward in that context (of a bird falling).
Showing usage patterns helps show that a construction is not typically used, but it does nothing to explain why it is awkward.
That’s a bit much detail to scribble in the notes of the margins of a paper. That kind of instruction deserves one-on-one conversation, or “feedback … negotiated with the student, and grounded in the content of writing”.
The point of the word “awkward” is not to be the final lesson or even the bulk of the feedback to the student - it is a margin note so the teacher has a clue what he/she meant by grading it down and can then go into that detailed instruction with the student. But that isn’t something that is likely to happen with the whole class, it requires either the student or the teacher specifically seeking individual feedback. The burden really is on the student to get that clarification of why it was “awkward”. (Does the teacher need to specifically write “see me after class for explanation”?)
Well, it’s entirely dependent on the context of the course, and the specific instructional goals of any particular task, but you’re speaking to my whole point. Maybe I need to be more blunt: there is no inherent reason why one such otherwise syntactically correct term is deemed “awkward” and another is not, other than the customs of usage. That’s the whole nature of language.
I believe (without being able to prove it, though I’m sure I could come up with examples that might not be exactly satisfactory) that there is always some inherent reason why a construction is judged syntactically correct but awkward. I think sometimes it could be a combination of things, where each one adds to the “overall awkwardness score”, and I think they are often (rightly) judged to be at once too complex and too individually trivial to bother explaining or haggling over.
I don’t think your test is the relevant one if we’re trying to explore the semantics of “midair” beyond the highly specific question that the OP raised - to which the answer appears to be “neither”.
“Falling in midair” is semantically quite different from “falling from of midair”/“falling out of midair”. The former indicates that the faller is passing through “midair” but has not left it. The latter both indicate that “midair” was the origin, but that the faller has now left it. I don’t think comparing the frequency of the complete phrases tells us much about how we use “midair”.
I noticed that the phrase “in midair” is vastly more common than either “from midair” or “out of midair”. My hypothesis is that “midair” semantically emphasizes the drama of the location, and is therefore more frequently used to describe a place where something happens, rather than a place from which something happens.
I don’t know if my hypothesis is correct, but the overall frequency of the various prepositions used with “midair” seems like a reasonable test for it.
Riemann, I appreciate and agree with your observations. Understanding the typical use of “midair” helps us assess the OP’s usage options.