Rava has a question: What is the halacha regarding something which you throw through a house, that goes in one window and out the other? Do we say that something that passes through the house's airspace is considered to have landed inside, or not?
This question is first posed on Bava Metzia 12a. While the Gemara there attempted to settle the issue based on the Mishnah there, on 11b, ultimately it rejected that proof, as the Mishnah discusses something which is rolling, which may be different than something which is flying.
The question later appears on 102a, where Rava seemed to pasken one way, when in fact he (as we saw above) remained doubtful about it. The Gemara answers that the case is different, as in 102a, the case was about something flying through the air and landing in someone's domain, while Rava asked about a case where it flew in the air and did not land in anyone's domain.
So, in summary, Rava's question remains unresolved.
It should be noted that the Gemara in Zevachim (25b) records a discussion between R' Asi and R' Yochanan regarding blood from a slaughtered karban-to-be which was falling into its bucket, but the bottom of the bucket fell off before the blood landed inside: do we say that the blood is considered to have landed already or not? Ultimately, the Gemara concludes, according to any of three versions of this question, that it is considered to have landed, but obviously this is parallel to the Gemara in BM 102a, rather than Rava's question from 12a.
The problem is that there's a Mishnah in Shabbos (96a) which records a dispute between R' Akiva and the Chachamim regarding one who throws from a private domain to another private domain through a public domain: R' Akiva holds he's chayiv, while the Chachamim say he's patur. The Gemara explains (97a) that they argue when it was thrown within 10 tefachim of the ground, so R' Akiva holds he's chayiv because throwing is like it's landed, while the Chachamim hold he's patur because throwing is not like it's landed. (If it was thrown above 10 tefachim, it's in a makom petur, and so it doesn't even matter one way or the other - it will be patur anyway.) This discussion is also brought down on 4a-b.
If this is the same as if it goes from a reshus harabim to a reshus harabim through a reshus hayachid, Rava should have resolved his question from here. Even if it's not, this should be the same as the case on BM 102a and Zevachim 25b, which resolved their questions from other sources, indicating in those Gemaras that the Gemara's conclusion follows everyone. Whichever case is more comparable, why does the Gemara not quote this Mishnah as a proof?
So why doesn't Rava resolve his question from this Mishnah, that his two sides to his question are exactly the dispute between R' Akiva and the Chachamim?