MH17 and MH370
The crash of MH17 occurred a couple days after the fast of the 17th of Tammuz, when the wall of Yerushalayim was breached, ultimately leading to the destruction of the Beit Hamikdash. Its wreckage is there for all to see, just like the absence of the Beit Hamikdash and the presence of the Shikutz Shomem is there for all to see.
On the other hand, MH370 disappeared on the 6th of Adar Bet, a day before the Yahrtzeit of Moshe Rabbeinu, which is observed by some as a fast day as well. 370 is the gematria of משה [Moshe] plus כה - which designates prophecy [see Sifri on Matot] and was the first word he was instructed to say to Par'oh. Regarding Moshe Rabbeinu, it says: וְלֹא-יָדַע אִישׁ אֶת-קְבֻרָתוֹ, עַד הַיּוֹם הַזֶּה [and no man knoweth of his sepulchre unto this day].